NHẬN BIẾT VÀ TÁCH CÁC CHẤT RA KHỎI HỖN HỢP (TÁI BẢN LẦN THỨ 5) - NGÔ NGỌC AN

8/9/2019 NHN BIT V TCH CC CHT RA KHI HN HP (TI BN LN TH 5) - NG NGC AN

1/179

NG NGC AN

NHN BITV TCH CAC CHTRA KHI HN HP

(Ti bn ln th nm)

NH XUT BN GIO DUC VIT NAM

WWW.FACEBOOK.COM/DAYKEM.QU

WWW.FACEBOOK.COM/BOIDUONGHOAHOCQU

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W.DAYKEMQUYNHON.UCOZ.COM

ng gp PDF bi GV. Nguyn Thanh T


2/179

Cng ty CP dch v xut bn Gio dc Gia nh - Nh xut bn Gio dc Vit Namgi quyn cng b tc phm.

24-2010/CXB/136-2242/GD M S: 8I057mO-TTS



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3/179

LI NI 6CI

rong nhng dng bi tp l thuyt ca mn Ho hc, dng bi nhn bit

cc cht, tch cht r khi hn hp v iu ch cc cht l dng bi hc sinh

thng lng tng. gii quyt loi bi ny ngoi vic nm vng l thuyt vtinh cht ho hc cc cht, cc em cn phi nhy bn trong vic pht hin s

khc nhau v tnh cht ca cc cht nhm nhn bit mt cht hoc tch mt

cht ra khi tp hp cc cht. gip cc em c k nng ny, chng ti bin

son cun schNhn bit v tch cc cht ra khi hn hp vi nhiu bi

tp a dng v cch nhn bit, tinh ch v tch cc cht ra khi hn hp. Sch

gm 2 phn:

Phn 1: Ho hc v c

Phn 2: Ho hc hu c.Trong mi phn c phn ioi cc dng bi tp theo cc ch . Hi vng

cun sch ny s gip cc em n luyn thi tt nghip Trung hc ph thng

v thi vo cc trng i hc vi kt qu tt.

Quyn sch c bin son trong iu kin tng i gp rt v kh nng

ca tc gi cng c gii hn, rt mong nhn c kin ng gp ca qu

ng nghip v bn c. Mi kin xin gi v Ban bin tp Khoa hc t nhin

- Nh xut bn Gio dc ti Thnh ph H Ch Minh - 231 Nguyn Vn C,

Qun 5, TP. H Ch Minh.



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5/179

PHN 1

H O V C

I. Nhng phn ng c trng ca kim loi, phi kim v hp cht

ca chng

1. Nhng phn ng c trng ca kim oi, ion kim [oi

2. Hng dn tch mt s kim loi v hp cht ra khi

hn hp ..... -

3. Nhng phn ng c trng ca phi kim, anion v cc

hp cht

II. Nhn bt v ch cc ch ra khoi hon hp

Ch 1: Nhn bit kim loi, io.n kim li v hp cht

ca chng

Ch 2: Nhn bit phi kim v hp cht ca chng

Ch 3: Tch cc kim loi, phi kim v hp cht ca chng

ra khi hn hp

III. iu ch cc cht v hdp cht v c

IV. Gu hi v bi p t gii

V. Hng dn gii



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P H N

HO V C

I . NHNG PHN NG C TRNG CA KIM LOI, PHI KIM V

CC HP CH T CA CHNG

1. Nhng phn Lig c trng ca kim loi, ion kim loi

Cht cnnhn bit

Thc th Hin tng Phng .trnh phn ng

(1 ) (2) (3) (4)

Kimloi kim

v ki.mth

h20 Dung dch trong +

H2T (vi Ca choung dch c)

M+ nH20 -* M(0H)n + - H2T

Li (LP) Tm ln a Pt.ri t trn nkh khng mu

Ngn la tia

KC) Tm

Na (Na*) Vng

Ca (Ca2+) da cam

Ba(6a?+) Vng.lc

Nguyn t lng

tnh Be. Zn, A,Cr

Dung dch OH"

(NaOH,Ca(0H)2)

Tan- + H2 ' M+ (4-n)H +.

+ {n-2)H2 M0jn'4+ - Hgt

M+(4-n)NaOH + (n-2 )H2~>

- Na4JVI02+ - H2T

Pb. HCI Kt ta trng + H2 Pb +2HCI -PbCI2 + Hjt

Cu

HN3long Kh NOkhng mu 3Cu + 8HNO3- 3Gu(N03)2+ 2N0+ 4H20

HNO3c Kh N2mu nu Cu +4HNO3 Cu{N03)2+ 2NO2T+ 2H2O

t trong 2 Mu (Cu) ->Mu en (CuO)

2Cu + O2* 2CuO

Au Hn hp HNO3c v HC ct l th tch 1:3

. Tan + NOt Au + HNO3+ 3HCI AuCt3+ NO++ 2H20

8a I Dung dch H2S04 iong

Kt ta ng vH2T

Be + H2SO4(ong >B2SO4+ H2t



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(1 ) . (2) (3) (4)

8a2tDung dch S0BaC03

Ca2*

Dung dch CO32' ' Kt ta trng Ca #+ CO22 >CC03-l

Dung dch SO42" Kt ta trng tan + SO/ >CaS4 t tan

Cu2tDung dch OH" Kt ta xanh Cu2*+ 20H~ Cu(OH)2

Dung Kt ta trng CuJf + C3 >CuC03-l

Mg+Dung dch 0H Kt ta trng Mg2, + 20H' Mg(OH)2l

Dung dch CO32' Kt ta trng Mg2*+ C3 *MgC03

Fe2+Dung dch OH' Kt ta trng xanh Fe2++ 20H' -> Fe(OH)2;

Dung dch C032" Kt ta trng Fe2"+ CO32"-> FeC03l

Fe~

Dung dch OH" Kt ta nu Fe3*+ 30H' Fe(H)3

Dung dch CO32" Kt ta trng 2Fe3++3C032- - Fe2(C03)3

Dung dch cr Mu vng Fe3t + 3CI' -> FeCI3

Ag*Dung dch OH Kt ta en Ag++ OH- - AgOH

Dung dch cr Kt ta trng Ag4 + cr -> AgCli

ai3+

Cho t t dungdch NaOH n

d

Lc u kt ta mutrng, sau tan trong

OH d

AI34+ 30H- -AI(OH)3 AI(OH)3+ OH -> AI02 + 2H20

Zn2+ Zn24+ 20H- -> Zn Zn022- + 2H20

Be2+ Be2*+ 20H- -* Be(OH)2 Be(OH)j + 20H' Be022~ + 2H20

Cr3* Cr3*+ 30H- -> Cr(OH)3Cr(OH)3+ OH' Cr2"+ 2H?0

2. Hng dn tch mt s kim loi v hp cht ra khi hn hp

V d 1:Tch ring tng kim loi Ag,Cu ra khi hn hp.

^ t tro lie khng kh + HC1' . CuCl - > CuAg S t trong khng khi HC1 Cu(Cu lc [Ag

V d 2:C hn hp bt CaO, MgO, lm th no tch ring, ccoxit ra'khi hn hp.

CaO V . * Ca(OH)2 CaCO; > CaO

MgO > MgO+ h 2o

----- >-

Loc ----->



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8/179

V d 3: C hn hp AI v mt s kim loi: Cu, Ag, Pb, bngphng php ho hc hy t ch AI ra khi hn hp kim loi.

A I v 1 +NaOH d

Hn hp KLJ L9C I---- Hn hp KL

+C02 t pncNaAlOa -* Al(OH)34- - A1203 - AI

V d 4: C hn hp bt MgO v Fe203, bng phng php hohc hy tch ring tng oxit ra khi hn hp.

- Cch 1 : Cho kh c o qua hri hp bt MgO v Fe23nung nng.

(JA __+NaOH t

' r M s 4 -+ Mg(OH)2 ^ Mgo^ c +HCI +NaOH_ 0 2>t^C Fe -> FeCl2 -> Fe(OH)2 Fe203FeL

- Cch 2 ; Ho tan hn hp trong dung dch HC1 ri in phndung dch.

_ +NaOH tUgO'] r MgCla'l MgCl2 -> Mg(OH)2 - MgO

I +HC1 J L {_ _ f I phn \ +HC1 +NaOH 02,tFe20 3J LFeClsJ Fe ^ FeCl2 Fe(OH)2 -> Fe203

V d 5: C hn hp S1O2, AI2O3, Fe20 3 - Bng phng php hohc tch ring cc oxit ra khi hn hp.

Trc tin nn cho hn hp tc dng vi dung dchHCl vS1Okhng tc dng vi axit HC1, lc ra c Si02.

Dung dch cn li AICI3 v FeCl3cho phn ng vi NaOH d thudc NaAl(>2 tan v k t ta Fe(OH)3> tip theo lc tch k t ta rinhit phn ta thu c Fe203. Dung dch NaA102ch tc dng vi khCO2ta thu c kt ta AI(OH)3, nhit phn c AI2O3.

Lu :

1. Cc oxit ca kim loi hot ng ho hc mnh nh K20, NaMgO, AI2O3 kh ng b kh bi cc ch t kh c o , H 2, c. . . , n u muniu ch cc kim loi ny th phi chuyn thnh mui cforua ri in

phn nng chy mui clorua.

- Mun iu ch kim loi kim v kim th ngi ta in phnmui clorua nng chy, khng dng mui sunfat SO42'. (kh nngchy), khng dng mui nitrat N03 (d n).



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9/179

- Ring iu ch AI th' in phn nng chy AI2O3, khng inphn nng chy mui nhm v mi ny thng hoa nhi t cao.

2. Mun tch cc oxit ca kim loi MgO v Fe203 ra khi hnhp, dng CO kh:

CO + MgO---- >khng phn ng

3CO -- F62O3 -> 2F e + 3 CO2

Cho hn hp rn ( ngui) sau phn ng tc dng vi H2SO4 cngui, MgO phn ng, Fe khng phn ng, lc c Fe v dung .dchMgS04. T MgS04 v Fe iu ch tr li MgO .v Fe20 3:

MgO + H2SO4 ---->MgS04+ H20

MgS04 + 2NaOHd - >Mg(OH)2 + Na2S04

. Mg(OH)2: :---> MgO + H20

Fe + H20 t>57Uc > FeO + H2t -

4FO + O2 -- > 2Fe23

Hoc iu ch Fe203 theo cc phng trnh sau: .

F e + H2SO4 long > Fe S0 4 + H 2t

FeS04 + ;2NaOH > Fe(OH)24- + Na2S04

4Fe(OH)2+ 02 > 2Fe203 +4H20

3. Mun lm kt ta hon ton in Ala+ nn cho dung dch AI3+tc dng vi duhg ch NH3-

Al3+ + 3NH4OH - AI(OH)3i + 3N V

4. Hai kim loi Fe v AI th ng vi cc axit HNO3 dc, ngui,H2SO4 c, ngui.

5. Dung dch mui no to mi trng axit, baz hay trung tnh? Dung dch mui ca axit mnh, ba20 yu tao mi trng axit

(qu tm ho ). , .

NH4++ H20 ^ = = NH3 + H30 +

Dung dch mui ca baz ninh, axit yu to mi trng baz(qu .tun ho xanh).



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10/179

V d:Dung dch Na2C03to mi trng baz

COs2' + H20 HCO3- + OH

Dung dch mui ca axit mnh, baz mnh to mi trng trung

tnh v khng thu phn.* Dung dch mui ca axit yu, baz yu thng thng to mi

trng trung tnh, tuy nhin i khi cn ph thuc vo thu phn ca axit hay bazo\ V

3. Nhng phn hg c trng ca phi kim, anon v cc hp cht

Cht cnnhn bit

Thuc th Hin tng Phng tnh phn ng

(1 ) (2 ) (3) (4}

f2 Kh mu lc nht

ClzNuc Br2

(mu nu)Nc bromnht mu 5C2+ 8r2+ 6H20 -> 10HCI +2HBr03

Dung dch KI +.h tinh bt

Khng mu -> miixanh

Cl2+ 2KI -> 2KC + i2 -Kt'

H tinh bt -4 Mu xanh

Br2

Cht lng mu nu

Niic clo Nc brom.nht mu 5CI2+ Br2+ 6H20 -> 10HC1.+2HBr03

Kh S2 Nc bromnht mu SO+8r2+ 2H20 H2S04+ 2HBr

*2

un nng Tinh th thng hoa (himu tm)

H tinh bt Khng mu chuynthnh mu xanh

02

Que m tn Bng chy

Cu (mu ),t CuO(mu en)2Cu + 02 -2CuO

SOs

Kh mi hc

Nc brom(mu nu) Nc bromnht mu SQ2+ B+ 2H20 ^ H2SO4 + 2H8r

. Dung dchthuc tm

Thuc tmnht mu 5S02+ 2KMn04+ 2H20 2H2S04++ 2MnS04+ K2S04

S03 Dung dch BaCI2 BaSO-l mu trng BaCI2+ S03+ H20 -> BaSC + 2HC!

h2sMi trng th

Dung dchPb(N03)2

Pbi mu en Pb2+ + H2S ^ PbSi + 2H+



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11/179

nh3

Mi khai

Qu tm m Qu tm ho xanh

HCI (c) To khi trng NH3+HC1 -> NH4CI

NO Kting khi Ho nu 2N0 + 02 2N02

NO2

Khi mu nu

Qu tm m Qu tim ho 3NO? + H20 - 2HNO3 + NO

Lmlnh Mu nu ->khng mu 2N02 -* N204

CO

Dung dch PbCI2 Pb4- mu vng CO +PbCI2+H20~> Pbi+2HCI +C02T

CuO{mu en),t

Cu (mu ) 'CO+ CuO >Cu+ CO2

COs Nc vi trong Lmvn c nc vi CO2+ Ca(0H)2 >CaC03i + H2O

Hz

t, lm lnh C hoi nc lm CuS04khan mu trng -> mu

xanh

2H2+ O2 2H2OCUSO4 +5H20 -> CuS04.5H20(trng) (xanh)

CuO(mu en),t .

Cu (mu )H2+ CuO > Cu+ H2O

H20 (hi) CuSO* khanmu trng

Mu trng - mu xanh C11SO4+ 5H20 *CuS0AqCIJ-

. Br AgBr mu vng nht Ag* + Br" - AgBri

r Agll mu vng sm Ag* + r - Agl

PO43" Ag3P04i mu vng 3Ag*+PCV^Ag3P04>l (tan trong H+)

WO3 H2SO4 c + Cu Kh N02t mu nu,dung dch mu xanh

Cu+ 4HNO3 -> Cu(N03)2+ 2N02 ++ 2H20

no 2- H2SO4 long, t Kh N02mu nu H2S0< + 3N


12/179

00

Dung dch Ba2+ BaC03 mu trng tantrong H*

Ba2++ C032" BaC03

Dung dch H+ Kh C02 CO32- + 2H+-> CO2+ H20

h so 3 Dung ch H+ Khi S02t HSO3 + H+ S02t' + H20 .

hc o3 Dung dch H+ Khi CDjt HC03 + H+-'COzT + HjO

I I . NH N BI T V TCH CC CHAT RA KH I H N HP

CH D 1 *

Nhn bit km loi, ion kim loi v hp cht ca chng

1. a) Bng phng php ho hc, hay phn bit 4 kim loi sau: Cu, Fe.

b) C 4 oxit ring bit sau: Na20, Al20 3, Fe203 v MgO.Lm th no c th nhn bi c mi oxit bng phng php ho hc viiu kin cc dng thm 2 cht.

HNG D N GII

a) Cho H2S04 c, ngui vo 4 kim loi:

- Ch c Cu, Zn phn ng:

Cu + 2H2S04c---- CuS04+ S02 + 2H20

Zn + 2H2SO4c ---- * Z11SO4+ SOt + 2H20

Sau Zn, Cu c phn bit bng HC1 long, nh dung dch HClong vo hai mu, mu no c si bt kh l Zn; mu khng tc dnl Cu.

Zn + 2HC1---- >ZnCl2 + Ht

- Cn li l AI v Fe, ly hai mu ny cho tc dng vi dung dcNaOH, mu no tan trong dung dch NaOH l Al, mu cn li l Fe.

2AI + 2NaOH + 2H20 > 2NaA102+ 3H2t

b) Cho H2O vo oxit trn ch c N20 tan to thnh dung dcNaOH, cho dung dch NaOH vo 3 oxit cn li, oxit no.tan l AI2OHo tan 2 oxit khng tan Fe203 v MgO trong dung dch HC1 FeCl3 v MgC2- Dng dung dch NaH tc dng vi tig dung dcmui ny to-kt ta trng, bn d l Mg(OH)2. Suy ra oxit ban u l



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13/179

. MgO. Nu thu c kt ta mu nu l Fe(OH)3, suy ra oxit banu l Fe2C>3(hc sinh vit cc phng trnh phn ng).

2. Ch dng mt ho cht, nu phng php nhn bit 4 mu km loi lMg, Zn, Fet Ba.

HNG DN GI

- Ly 4 ng nghim, mi ng cha mt t dung dch H2SO4, choln lt tng kim loi vo cc ng nghim trn, ng no c bt kh

bay ra v xut hin kt ta l Ba.

Ba + H2SO4 ---- >BaS04 + H2T

Cc ng cn li u c bt kh v -to thnh mui tan MgS04 ,Z11SO4, FeS04.

- Cho tip Ba d vo ng nghim c BaS04i, xy ra tip phnng sau: '

* Ba + 2H20 > Ba(OH)2+ H2T

Lc b kt ta, cn li dung dch Ba(OH)2dng lm thuc th.

+ Ly dung dch Ba(OH)2cho vo 3 ng nghim cha cc kim loicn li, ch c ng nghm cha Zn c phn ng v c kh bay ln:

Zn + Ba(OH)2 +BaZnO2 + H.2t

+ Cho tip Ba(OH>2vo 2 ng nghim cha cc dung dch MgS04,FeS04 c 0 trn. ng nghim c kt ta trng, v khng mukhi da ra khng kh l Mg(OH)2- T nhn bit c Mg.

MgS04+ Ba(OH)2 -> BaS04i + Mg(OH)24

ng nghim c kt ta trng sau chuyn sang n l ng chadung dch FeS04.

FeS04+ Ba(OH

)2 >BaSC + Fe(OH

)2

4Fe(OH) + 02+ 2H20 ---- >4Fe(OH>3 (mu nu)

. T nhn bit dc Fe.

3. C 3 l ng ba hn hp dng bt: (AI + AI2O3), (Fe + Fe20 3) v (FeO +Fe20 3); Dng phng php h hc nhn bit chng. Vit cc phng trnhphn ng.



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14/179

HNG DN GII :

- Cho hn hp ln lt tc dng vi dung dch NaOH, hn hpno c. kh bay ra l (AI + AI2O3).

2NaOH + AI2O3 > 2NaAI02+ H202NaOH + 2AI + 2H20 - 2NaAI02+ 3H2t

- Hai hn hp cn li (khng tc dngvi NaOH) chotc dngvi dung dch HC1, hn hp no c kh bay ra l (Fe +Fe20 3). Hnhp khng c kh bay ra l (FeO + Fe203 ).

Fe + 2HC1---- FeCl2+ H2t

Fe203+ 6HC1 ---- >2FeCls + 3H20

FeO + 2HC1---- ->FeCl2+ H20

4. Ch c dng thm mt thuc th, hy tim cch nhn bit cc ungdch (mt nhn) sau y: NH4HSO4, Ba(OH)2, BaCl2, HCI, NaCl, H2S04. Vitcc phng trnh phn ng.

HNG DN GII

- Cho qu tm vo cc ng nghim cha cc dung: dch trn, qutm ho xanh l dung dch Ba(OH)2, ho l cc dung dch HC1,

H2SO4, NH4HSO4 (nhm .I) v qu tm kh ng i m l B aC ls, N aC l(nhm II).

- Cho mt t dung dch Ba(OH)>vo cc dung dch nhm I, dungdch no cho kt tua mu trng BaS04 l H2SO4, dung dch c kt taB a S04 v c mi kh ai (NHs) l NH4HSO4, dng dch khng c k t ta

lHCl. .

Ba(OH)2+ H2S04 ---- >BaS04i + 2H20

Ba(OH)2

+ NH4HSO

4

---- >BaS04 + NH3

T + 2H20Ba(OH)2+ 2HC1 >BaCl + 2H20

Cho mt t dung dch H2SO4 ( nhn bit trn) vo dung dch

nhm II, dung dch no cho kt ta l BaCla, dung dch cn li khngphn ng l NaCl.

5. Ch dng thm nc, hy nhn bit 4 cht rn: Na20, A2O3, Fe20 3) AIcha trong cc l ring bit. Vit cc phng trinh phn ng.

(Trch t tuyn sinh i LC, Cau ng nni 2003, khi A)



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15/179

HNG DN GII

- Ly mt t mi cht rn cho vo tng ng nghim cha nc.

Cht rn no tan l Na20:

Na20 + H20 ---- >2NaOH

- Ly mt t mi cht rn cn li cho vo tng ng nghim chadang dch NaOH. thu c trn. Cht no tan v c bt kh thot ral Al:

2A1 + 2NaOH + 2H20 ---- >2NaA102+ 3H,

Cht no ch tan l AI23:

A1203+ 2NaOH >2Na102 + H2O

Cht no khng tan l Fe20 3.6 . C th nhn bit cc dung dich sau y ch bng giy qu tm c

khng? Nu c hy gii thch: H2SO4, Ba(OH)2, BaCI2l HCl, NaCI, NaOH.

HNG DN G1

Nhn ra dung dch HC1, H-2S0 4 lm qu tm ho (nhm I).

Nhn ra dung dch Ba(OH)2, NaOH lm qu tm ho xanh(nhm II).

Nhn ra dung dch NaCl, BaCl-a khng lm i mu qu tm(nhm III).

- Ly ln lt dung dch nhm I vo 2 dung dch nhm II, nuc kt ta mu trng th nhn ra cp H2SO4 v Ba(OH )2 cp cn li

khng c kt ta l HC1 v NaOH.

H2S04+ Ba(OH)2 ---- BaS04i + 2H20

- Ly ln lt dung dch nhm I vo 2 dung dch nhm III,

nu c kt ta mu trng th nhn ra cp H2SO4 v BaCl2, cp cn likhng c kt ta l HC1 v NaCl.

H2S04 + BaCl,---- >BaSC + 2HC1

Nh vy c th nhn bit cc dung dch trn ch bng qu tm.

7. C 4 l mt nhn c nh s t 1 n 4 cha cc dung dch KI,AgN03, HCt, Na2C 03. Hy xc nh s ca mi dung dch nu bit:

- Cho cht trong l 1 vo cc l u thy c kt ta.



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16/179

- Cht trong l 2 ch to kt ta vi 1 trong 3 cht cn li.

Cht trong l 3 to mt kt ta v mt kh bay ra vi 2 trong 3 cht cn li.

HNG DN GII

Cht trong l 1 to kt ta vi cc cht trong cc l th chtrong l 1 l AgNC>3.

AgNOa + K I---- >AgU + KNOa

A g N 0 3 + H C1 > A g C l i + HN 0 3

2gN03 + Na2C0 3 ----> Ag2C03>l' + 2NaN03

Cht trong l 3 to mt kt tua v mt kh bay ra vi 2 trong cht cn li th cht trong l 3 l Na2C0 3, cht trong l 4 l HC1.

2AgN03+ Na2COs ---- >Ag2C0 3 'l' + 2N8LNO3

Na2C03+ 2HC1----

2NaCI + C 02t + H20Cht trong l 2 ch to kt ta vi 1 trong 3 cht cn li th ch

trong l 2 l KI.

8 . C 4 l mt nhn A, B, c , D cha cc ung dch HCI, CaCl2, NaHC0Na2C 03. Hy xc nh cc cht trong mi l v gii thch, nu bit:

- Cho cht trong l A vo l c thy c kt ta.

- Cho cht trong t c vo l D thy c kh bay ra.

- Cho cht trong l B vo l D thy c kh bay ra.

HNG D N GI I >

Dung dch trong l c va to kt ta, va to kh bay ra khi tdng vi hai dung dch khc nn dng' dch trong l G l Na2C0Dung dch trong l A l CaCl v ung dch tong l D l HC1, undch trong l'B l NaHC03.

Phng trnh phn ng:

Na2C03+ 2HC1---- > 2NaCl + C02T + H2

Na2C0 3+ CaC2 ----- CaC03 + 2NaCl

NHCOs + HC1> NaCl + C02t + H20

9. C .2 dung dch: dung dch A v dung dch B. Mi dung cch ch chaloi cation v 2 loi anion trong s cc ion sau:



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17/179

K+ (G,15 mol); Mg2+ (0,1 mol); NH4+(0,25 mol); H+ (0,2 mol); cr (0,1 mol);SO42"(0,075 mol); NCV {,0,25 mol); C032 (0,15 mol).

Xc nh dung dch A v dung dch B.

HNG DN GII

Dung dch A: NI4+(0,25); K+(0,15); CO32 (0,15); c r (0,1)

Tng in tch dng = Tng in tch m

(0,25 + 0,15) = (0,15 X2 + 0,1)

Dung dch B: H+(0 ,2 ); Mg2" (0,1); NOs' (0,25); S042' (0,075)

Tng in tch dng = Tng in tch m

0,2 + 0,1 X 2 = 0,25 + 0,075 X 2

1 0 . Ch c nc v kh C02 lm th no nhn bit c cc cht rn sau:

NaCI, Na2C03, CaC03, BaS04. Trnh by cch nhn bit mi cht v vitphng trnh phn ng {nu c).

HNG DN GII

- Ho tan tng. cht vo nc, thu c hai nhm cht:

+ Nhm tan trng nc gm NaCl v Na2C03


18/179

S0 32 + 2H +- V S0 2t + H20

CO32' + 2H+---- >C02t + H20

Cho hn hp kh ln lt qua dung dch KM11O4 v sau l dundch Ca(OH)2. Ta nhn thy:

- Dung dch KMn04b nht mu do SO2phn ng:

5S02+ 2KMn04+ 2H20 ---- >K2SO4+ 2 M11SO4 + 2 H2SO4

Chng t hn hp kh c S02, suy ra dung dch A c ion SO32'.

- Dung dch Ca(OH)2 b vn c hoc vn c ri tr' nn tronsut do cc phn ng:

C02+ Ca(OH)2 ---- >CaCOai + H20

C02+ CaC03+ H20 ---- >Ca(HC03)2

Chng t trong hn hp c kh C02, suy ra trong dung dch A cion CO32.

- Cho dung dch BaC2vo dung, dch B ta thy c kt tda:

SO42' + BaCl2 > BaS04i + 2C r

Chng to trong dung dch A c ion SO42".

Cch 2:~Cho dung dch BaC2vo dung dch A hn hp kt ta c .

S42- + Ba2+ -> BaSC

SO32 + Ba2+ -BaS03i

C032"+ Ba2+ >BC03

Cho kt ta c tc dng vi dung dch HC1:

+ Cht khng tan l BaS04, suy ra trong dung dch A c ion SO42".+ .Cht tan l BaCCV v BaSC>3.

Cho tc dng vi dung dch- HC1, thu c hn hp kh CO2 vSO2. Nhn bit kh S2, CO2 suy ra ion SO32' v ion C032- nhcch 1 .

12. Ch dng mt kim li nhn b[t cc dung dch sau: AgN03, NHC v NaN03. Trinh by cch tin hnh v vit cc phng trnh ho h

minh ho.



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19/179

HNG DN GII

Dng kim loi ng. Cho kim loi Cu vo cc mu th cha ccdung dch AgN03, NaOH, HC1 v NaN03j mu th no c dung dchmu ;xanh lam l AgN03.

Gu + 2AgN03 ---- >Cu(N03)2 + 2AgCho dung dch AgN3 vo cc mu th cn li, mu th no cho

kt ta trng l HC1.

H C1+ AgN03 A g C li + HNOa

Dng Cu(N3)2 l sn phm to thnh nhn bit dung dchNaOH.

Cu(N03)2+ 2NaOH---- > Cu(OH)2 + 2NaN03

(Mu xanh)Cn li l NaNC>3:

13. Dng mt ho cht phn bit cc dung dch sau: BaCi2l Na2S04,Na3P 04, HN03. Vit cc phng trinh phn ng minh ho.

HN G DN GI1

Cho dung dch AgN3 vo cc mu th cha cc dung dch trn,dung dch mu th no cho kt ta trng AgCl l BaCl2, kt ta muvng Ag3P0 4l Na3P04.

2AgN3+ BaC2 ---- 2AgCll + Ba(N3)2

Na3P0 4+ 3AgNOa ---- Ag3P 0 4i + 3NaNOs

Cho hai dung dch mu th cn li vo kt ta Ag3P0 4, dung dchmu th no ho tan Ag3P0 4 la HNO3.

Ag3P0 4+ 3HN03^ 3AgN03+ H3P0 4

Dung dch khng ho tan kt ta l dung dch Na2S04.

14. Dng mt ho cht phn bit cc dung dch sau: H2SO4, Na2S04,Na2C 03 v FeS04. Vit phng trnh phn ng minh ho.

HNG DN GII

Cho dung dch NaOH vo cc mu th cha cc dung dch trn,mu th no c kt ta trng l FeS04.

FeS04+ 2NaOH---- >Fe(OH)2+ Na2S04

Ly 3mu th cn li cho tc dng vi Fe(OH)2, cht no lm tanFe(OH)2 l H 2 S O 4 .



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20/179

Fe(OH)2+ H2S04 FeS04+ 2H20

Dng dung dch H2SO4 nhn bit hai mu th cn li, mu th

no c kh bay ra l Na2CC>3.

H2S04 + Na2C0 3 ---- >Na2S04+ C02t + H20

Cn i l Na2S4.15. a) C 5 l m t nhn, m i ng mt trong cc dung dch sau

NaH S04> KHC03i Mg(HC0 3 )2, Na2SC>3, Ba(HC03)2. Trinh by cch nhn bitng dung dch, ch c ng cch un nng.

b) Ch dng mt bo cht, hy cho bit cch phn bit Fe 20 3 v Fe30 4Vit cc phng trnh phn ng xy ra.

(Trch thi tuyn sinh i hc, Cao ng nm. 2002, khi B)

HNG D N GII

a) Ly mt t dung dch trong mi l cho vo cc ng nghnh s tng ng v un nig, quan st hin tng:

- 2 ng nghim s thy c kt ta trng xut hin, l ccng nghim cha dung dch Ba(HC0 3)2v Mg(HC0 3>2.

- 3 ng nghim cn li khng c kt ta.

- Ly vi git dung dch ' mt trong hai l ng cc dung dch c

k t. ta khi un nng trn, nh vo cc ng nghim ng cc dungdch khc. ng nghim thy c si bt kh l ng ng dung dchNaHS04j nu trong ng nghim ny to dung dch trong sut th dungch nh l Mg(HC03)2.

2NaHS04+ Mg(HC03)2 ---- >Na2S04+ MgS04+ 2 CO2T + 2 H2O

Nu trong, ng nghim c kt ta trng, thi l ng ng

Ba(HC03)2.

2NaHS04+ Ba(HC03)2 ---- BaS04i + Na2S4+ 2 C0 2t + 2H0ONh vy ta tm c cc l ng NaHS04, Ba(HCC>3)2,

Mg(HC03)2- Cn li hai dung dch cha bit l KHCO3v Na2S03.

Ly vi git dung dch Ba(HC03) bit nh vo Hai ng nghimng hai dung dch cha hai cht cha bit trn. ng nghim nothy xut hin kt ta th l dung dch NaSCV



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21/179

Ba(HC03)2+ Na2SOg >B aS03 + 2NaHC03

Dung ch cn li KHCO3.

b) Cho tng cht tc dng vi dung dch HNO3 long, cht phnng cho kh khng mu, ho nu trong khng kh l Fe304, cht phn

ngkhng cho kh J Fe20 3.' 3Fe30 4 + 28HNO3 ---- >9Fe(N03)3 + NO + 14H20

2NO + O2 - > 2NO2(mu nu)

Hoc c th dng HNO3 c:

Fe30 4+ lOHNOs 3Fe(N03)3+ NO2+ 5H20

Fe203 + 6HNO3 > 2Fe(N03)3+ 3H20

16. a) Dng phn .ng ho hc nhn bit tng kim loi sau: Al, Ca, Mg

v Na.

b) C 4 cht rn ng trong 4 l ring bit (khng c nhn) l: Na2C03,CaC03, Na2S04, CaS04.2H20. Lm th no d c th nhn bit tng cht

ng rong mi l, n a ch-dng H20 v dung dch HCI.

HNG DN GII

a) .Cho 4 kim loi tc ng vi nc, hai kim loi tc dng vi

nc l Ca, Na.^Hai kim loi khng tc dng vi nc nhit thng l AI v Mg. .

Ca + 2H20 ---- Ca(OH)2+ H2

2Na + 2H20 >2NaH + H2

Dng kh CO2 nhn ra dung ch Ca(OH)2v NaOH. T suyra kim loi l Na v Ca. ng dung dch NaOH nhu ra AI. Chtcn li l Mg (hc sinh vit tip cc phng trnli phn ng cn li).

b) Cho nc vo 4 mu th cha 4 cht rn, ta c th chia cccht lm hai nhm.

Nhm 1 : gm cc cht tan trong nc l Na2C3v Na2S0 4.

Nhm 2: gm cc cht khng tan trong nc l CaC3 vCaS04.2H20 .. ;



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22/179

Cho dung dch HC1 vo nhm 1 , ch t no gii phng kh lNa2C3, cht cn li l Na2S04. Cht no nhm 2 tc dng vi ungdch HC1 gii phng kh l CaC3, cht cn li ca nhm ny lCaS0 4.2H20 (hc sinh vit cc phng trnh phn ng).

17. C 5 dung dch ring bit sau: HCI, HN03dc, NaN03, NaOH, AgN03.Hy nhn bit mi ung dch bng phng php ho hc vi iu kin chdng kim loi nhn bit

HNG D N GI I

- C th dng kim loi.Cu nhn bit dung dch AgN03v dungdch HNO3c.

Cu + 2AgN03 ---- >C u (N O s )2 + 2Ag (ph ngoi ng)

(mu trng)Cu + 4HNO3 ---- > Cu(NOs)2 t 2NO2T t 2H20

(mu nu)

- Cho kim loi Fe .vo 3 dung dch cn li, dung dch no tc dngvi Fe c kh bay ln l HCL

Fe + 2HC1 * FeCl2> H2t

- Cho kim loi AI vo 2 dung dch cn li, dung ch no tc dng

vi AI v c kh bay ra l NaOH, dung dch khng c phn ng g lNaNOs-

2A + 2NaOH + 2H20 ---- 2NaAI02 + 3H2t

18. Dng 2 ho cht nhn bit 4 cht bt l K20, BaO, p 205v Si02.Vit phng trnh phn ng.

HNG D N G

Cho nc vo cc mu th cha cc cht bt trn, cc cht bt

tan, tr S1O2khng tan.

K20 + H20 2KO H

BaO + H2O ---- >Ba(OH>2

- P2O5+ 3H20 - 2 H3PO4

Cho giy qu tm vo cc sn phm va to ra c 2 dung dch lmqu tm ho xanh l dung dch KOH v Ba(OH)2, dung ch lm qutm ho l H3PO4- Cho dung dch H3PO4 vo 2 dung .dch lm qu



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23/179

tir ho xanh, dung dch no to kt ta l Ba(OH)a, dung dch cn lilKOH.

3Ba(OH)2+ 2H3P 0 4 ---- * Ba3(P0 4)2 + 6H20

19. Dng mt ho cht phn bit cc dung dch sau: BaCI2, K,

Fe(N03)2, AgN03v Na2C 03. Vit cc phng trnh ho hc minh ho.

HNG DN GI

Cho dung dch HC1 vo cc mu th cha cc dung dch mui, tanhn thy c mt mu th cho kt ta trng l AgN3 v mt muth c kh bay ra l Na2C0 3.

AgNOs + HC1---- >AgCU + HN03

Na2COs + 2HC1---- >2NaCl + C02t + H20

Dng AgN3 cho tc dng vi cc mu th cn li, c 1 mu thkhng c phn ng l Fe(N03)2cn 2mu th u cho kt ta:

AgN03+ K I---- >Ag + KNO3

2AgN3+ BaCl2 ---- >2AgCl + Ba(N0 3)2

Cho dung dch Na2C3 vo 2 mu th cha 2 dung dch KI v

BaC2, mu th no cho kt ta trng lBaCl.2, mu th cn li l KI.Na2C0 3+ BaCl2 ---- >BaC3'l' + 2NaCl

20. C mt hn hp cht rn gm (NaOH, Na2C 0 3, NaHC03) cho hn hp

tan vo nc c dung dch A. Hy nhn bit cc ton c trong dung dch A.

HNG DN G

Cho hn hp vo nc xy ra cc phn ng:

NaOH + NaHCOs----

>Na2C03+ H20Tu theo quan h v lng gia NaOH v NaHC03 ctrong hn

hp m xy ra 3 trng hp sau:

Trng hp 1: nNaOH = nNaHC0. -> Dung dch A ch c ion Na! v

CO32-.

Trng hp : nNa0H > n Nair0 -> Dung dch A tn ti cc ion

Na+, OH" v CO32"-



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24/179

Trng hp 3: nNaOH < nNaHCo3 - Dung ch A tn ti cc io

Na+, HC03", COs2-.

N h n b i t :

lon Na+, dng a Pt nhng vo trong dung dch ri a l

ngn n kh khng mu, ngn la n kh c mu vng. Ion CO32", c hai cch nhn bit.

- Cho t t HCI vo dung dch A thy si bt kh

2 H++ COs2---- >H20 + COzt

- Gho BaCl2vo dung dch A th xut hin kt ta

Ba2+ + CO32' ---- >BaC03

Ion OH : Lc b ht kt ta BaC03, cho MgCl2 vo dung dcnc lc ta thy xut hin kt ta trng:

Mg2* + 20 IT ---- >Mg(OH)2i (mu trng)

lon HC03~: L c b kt ta Mg(OH)2, cho dung ch Ba(OH)2vdung ch nc lc, thy xut hin kt ta:

Ba(OH)2+ 2HCO3 ---- >BaCOs-l + 2HzO + C032"

21. C 4 cc ng 4 cht sau: nc, dung dch NaCI, dung chdung dch Na2C 03. Khng dng ho cht no khc, hy nhn bit tng cht.

HNG D N G I

Ly mi dung dch mt t ri t t vo nhau theo tng cp thnhn thy khi cho HC1 vo dung dch Na 2C03 hay cho Na2C03 vHC1 u c kh bay ra:

2 HC1+ Na2C03-> 2NaCI + C0 2t + H20

Cp cn li kh vo nhau khng c phn ng, nn ta chia cht thnh 2 nhm.

Nhm 1: H20 v dung ch NaClNhm 2: Dung dch HC1 v dung dch Na2C0 3.

un n cn hai cc nhm 1 , cc khng c cn mui l nc, cc cn mui l NaCl.

un n cn hai cc nhm 2, cc khng c cn mui l HC1, cc cn mui l Na2C3.



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25/179

22. Cho cc oxitkim loi K20, Al20 3, CaO, MgO. Nu cch phn bit tngoxit khi ch c dng thm mt ho cht. Vit cc phng trinh phn ng.

HNG D N GII

Cho nc vo 4 oxit trn K20, CaO tan, cn li AI2O3, MgO khng tan.

KzO + H20 ---- >2KOH

CaO + H2O>C(OH)2(huyn ph, vn c)

Dng dung dch KOH va to ra lm tan AI2O3, nhn ra AI2O3cn MgO khng phn ng

A1203+ 2KOH---- >2 KAIO2+ H20

23. C 6 gi bt mu trng tng nhau: CuO, FeO, Fe30 4) Mn02, Ag20 v hn hp Fe + FeO. Ch dng thm dung dch HCI c th phn bit 6 gi bt khng? Nu dc hy trnh by cch phn bit.

HNG D N GIHo tan tng gi bt trong dung dch HC1

CuO + 2HC1 CuCl2+ H20 dung dch mu xanh

Mi02+ 4HC1---- MnCl2+ 2H20 + Cl2t kh mu vng nht

A g20 + 2H C 1 1>H2O + 2A gC l't m u trng

FeO + 2HC1---- >FeCls + H20

Fe30 4+ 8HC1---- >FeCl2+ 2FeC3+ 4H20

Fe + 2HC1---- >FeCl2+ H2f khng mu

FeO + 2HC1---- FeCl2+ H20 kHng mu

Dung dch FeCl3mu vng nht, c th phn bit FeO v Fe304jta ly 2 dung dch ho tan trong HC1 va d (tc dung dch FeCl2vdung dch FeC2 + FeC3) v cho thm hn hp bt FeO. + Fe lc mu vng nhat b bin mt hon ton. .

2FeCl3+ F e ---- >3FeCl2

24. C 5 mu kim loi: Ba, Mg, Fe, Ag, AI. Nu ch c H2S.O4 long(khng c dng bt ki cht no khc k c qu tm, nc nguyn cht) c th nhn c nhng kim loi no?

HNG D N GII

Cho 5 mu kim loi vo 5 ng nghim cha dung dch H2SO4long. ng nghim no khng c bt kh thot ra l Ag. ng nghim



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26/179

no c kh thot ra v c kt ta trng (BaS04) l Ba. Cn cc ngnghim khc t cc mui FeS04, A12(S04)3, MgS04v kh hiro. -

Trong cc ng nghim sau khi tm thy Ba, lc b kt ta BaS0c dung dch Ba(OH)2 (khi cho Ba vo ung dch H2SO4 u tin

Ba + 2 H2O ---- >Ba(OH)2+ H2T).

Cho 3 kim loi cn li vo 3 ng nghim cha dung dch Ba(OH)2,ng nghim no c kh bay ra v kim loi tan l AI.

2 AI + B(OH)2+ 2H20 -Ba(A102)2+ 3H2

ng thi ly dung dch Ba(pH )2 cho vo 2 dung dch MgS04FeS04, ng nghim no c kt ta trng ri'bin thnh mu nu lFeS4ng vi kim loi Fe (hc sinh vit cc phng trnh phn ng),ng nghim cn li l MgS04ng-vi kim loi Mg.

25. Dng mt ho cht phn bit 4 cht rn: NaC, Na2C3, BaC03BaS04. Vit cc. phng trnh ho hc minh ho.

HNG D N GII

Ln lt cho 4 cht vo 4 ng nghim ng dung dch HC1, nutan l NaCl' khng tan l BaS04j tan c kh ba ra l Na2C03 v

BaCOs-Na2C03+ 2 HCI > 2NaCi + C02+ H20

BaCOs + 2 HC1 ---- BaCl2+ C02+ H20

Sau , ly mt trong hai cht {Na2C03 hoc BaCOs) cho vodung dch sau phn ag trn, nu cht b vo tan trong dung dch nyv kt ta trong dung dch kia th l Na2CC>3(cht cn li l BaC03).

Na2c3+ BaCl2 ----

> 2NaCl + BaCOgiNu cht b vo khng tan trong c hai dung dchth n l

BaC03(cht cn li l Na2CC>3).

26. C 4 l ng dung dch NaHC03) CaCI2l Na2C03, Ca(HC03)2. Khngdng ho cht no khc, hy phn bit 4 l mt nhn trn.

HNG D N G

mt mu th vo ba mu th cn li, ta thu c theo kt qu

bng sau:



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27/179

Ca(HC03)2 NaHCOs CaC2 NasCOs

Ca(HC03)2 CaC03

NaHCOa

CaC2 CaC03i

Na2C03 CaCOsi CaCOgl

- Qua kt qu bng trn ta nhn thy c mt mu th vot t c cc mu th cn l khng thy du hiu kt ta, mu th NaHCOa-

- Mu th no thy c 2 ln kt ta vi cc mu th kia, mu th

l Na2C

3.Na2C03+ CaCl2 ---- >CaC3 + 2NaCl

Na2C03+ Ca(HC03)2 ---- * CaC0 3 + 2NaHCOs

- phn bit hai mu th cn li c cha CaCl2 v Ca(HC03)2,un nng hai ung dch ny, dung dch no c kt ta l Ca(HC03)2.

Ca(HC03)2 CaC0 3 + C02 + H20

27. Trong mt dung dch c cha cc ion C a2+, Mg2f, SO 42", N a + v GI '.

Bng phn ng ho hc v hin tng no chng t s c mt cc ion nytrong dung dch.

HNG DN GI

- Ion Na+: nhng a Pt vo dung dch ri a ln ngn n khkhng mu, thy ngn la c mu vng, chng t trong dung dch cion Na*.

- lon Mg2* v Ca2+: Ly mt t dung dch, nh dung dch NaOHd vo, thy c kt ta trng, em ho tan trong nc d m khngtan l Mg(OH)2.

Mg+ + 2 0 H >Mg(OH)2i (mu trng)

Lc ly phn nc lc Ca(OH2, sc kh CO2vo c kt ta, nu dkh CO2kt ta tan, chng t c ion Ca2+.

Ca2+ + 20H "---- >Ca(OH)2

CO2+ Ca(OH)2 ---- CaCOsi + H20

CaC03+ C 02+ H20 . = Ca(HC03)2



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28/179

Ion SO42 Nh Ba(N3)2 vo dung dch thy c kt ta trng l BaS04, chtig t trong dung dch c ion S042".

Ba(N03)2+ SO42- >BaS0 4 + 2N(V

Ion C: Sau khi loi b ht ion SO42" t phn ng trn, nhdung dch AgN03vo thy c kt ta trng AgCl, chng t trong dundch c ion cr.

Ag* + c r----->AgCU

28. C 4 kim loi di dng bt Mg, AI, Fe, Ag ng trong 4 l mt nhDng cc phn ng ho hc cn thit xc nh tng kim loi y.

HNG DN G I

- Cho dung dch NaOH vo 4 ng nghim cha cc bt kim lotrn, ng nghim rio c kh bay ra l bt Al.

2AJ + 2NaOH + 2H20 ---- >2NaAI02+ 3H2T

- Cho dung dch HC1 vo 3 ng nghim cha cc bt kim loi cli, ng nghim no c bt kim loi khng tan l Ag.

Mg + 2HC1---- MgCl2+ Hat

Fe + 2HC1---- >FeCl2+ H2T

- Cho dung dch NaOH vo dung dch MgC2 v FeCl2 ph

bit Mg v Fe.MgCl2+ 2NaOH > Mg(OH)2i + 2NaCl

(mu trng)

FeCl2+ 2NaOH----> Fe(OH)2 + 2NaCl(mu trng)

Sau an hai kt ta, kt t khng di mu lMg(OH)2 cng vi kt ta lc u mu trng sau chuyn thnhmu vng nl Fe.

4Fe(OH)2+ 0 2+ 2HsO ---- >4Fe(OH)j(vng nu)

29. Ch dng nc, kh cacbonic hy nu phng php phn bit 5 l btrng mt hhn l: NaCI, Na2S 0 4, CaC0 3 , Na2C0 3 , BaSO*..

HNG D N GIA1

Cho 5 cht vo 5 ng nghim c nc thy c 3 cht tan lNa2S0 4, Na2C3, NaCl v 2 cht khng tan: CaC03, BaS04.



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29/179

- Ta sc kh C02vo ng nghim .cha 2cht khng tan, thy cmt cht .tan . l CaC03.

CaC03+ C2 + H2O V. - Ca(HC03)2

' Ly dung dch Ca(HC03)2 va thu c cho vo 3 ng nghimcha mui natri, thy mt ng nghim khng to kt ta NaCl, cnhai ng nghim kia to kt ta trng:

Ca(HC03)2+ Na2S04 >CaS04i + 2NaHC03

Ca(HC03)2+ Na2C03 ---->CaC03* + 2NaHC03

- Sc kh C02vo 2 kt ta va to thnh, thy mt kt ta tan l CaC03, suy ra dung dch ban u l Na2C03, kt ta cn likhng tan l CaS04, suy ra dung dch ban u Na2S04.

30. a) C 3 ng nghim, mi ng c 2 cation v 2 anion trong s cc ionsau: NH4 , Na+, A g \B a 2+, Mg2+, Al3+ v cr , s 2', N03, S0 42, PO43 , C032~.

Hy cho bit cc cation v anion trong mi ng nghim (cc ion trong ccng nghim khng c ging nhau).

b) C 5 ng nghim ng ring bit 5 dung dch khng mu l NaCI,BaCI2, Ba(l\l03)2, Ag2S 0 4 v H2SO4. Khng dng cc ho cht khc, lm thno xc nh e.tng cht trong ng nghim?

HNG DN GII

a) ng 1 cha cc 1011: Na+, N H /, P 043-, CO32"ng 2 cha cc ion:Ba2*,Mg24-, s 2, Cl

ng 3 cha cc ion: Ag+, Al3+, NOa~> SO42'

b) - Nhn bit NaCl: Nu cht no to c kt ta mu trngvi mt cht, cn khng c hin tng gi vi 'ba cht cn li th cht phi l NaCl v:

NaCl + BaC2: khng c hin tng phn ng

NaCl'+ Ba(N03)2: khng c hii tng phn ngNaCl + H2S04: khng c hin tng phn ng

2N a C l + A g2S 0 4 N a2S 0 4 + 2AgGl l (m u trng)

- Nhn bit AgsS04: Nu cht no to c k t ta vi3 cht,cht cn li khng c hin tng g thi cht em th l Ag2S0 4 v nto kt ta AgCl v BaS4 v khng phn ng vi H2SO4.



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30/179

- Nhn bit H2S4: Dng Ag2S04nhn ra H2SO4 trong 3 ungdch cn li. Ag2S04khng phn ng vi H2S04j nhng to kt ta .vhai dung dch cn li.

- Nhn bit BaCl.2 v Ba(NOa)2- Cho H2SO4 va vo hai dung

dch cn li:BaClz + H2SO4 ---- >2HC1 + BaS04i

Ba(N03)2 + H2S04 ---- 2 HNO3 + BaSCLc b kt ta BaS04, cho dung ch Ag2SQ4 vo hai dung dch

nc lc sau phn ng trn, nu trng hp no cho kt ta trngAgCl th dung dch c cha Cl", c ngha l ta xc nh cdung dch BaC2 v phn dung dch khng to kt ta l HNO3, cngha ta nhn bit c dung dch: Ba(N3)2.

31 .'C.4 ng nghim nh s 1 , 2, 3, 4 cha mt trong 4 dung dch sauy: Na2C03, FeCI2, HCI v NH4HCO3. Ly ng 1 vo ng thy c kt taxut hin, ly ng 3 vo ng 4 thy c kh bay ra. Xc nh cc ho chng trong mi ng nghim.

HNG D N GII

- Khi ng 1 vo ng 3 thy c kt ta, do ng 1 v ng 3phi cha Na2C3v FeCl2v:

Na2C03+ FeCl2 ---- FeC03i + 2NaCl

- Ly ng 3 vo ng 4 thy c kh bay ra, vy ng 3 phi chaNa2C03v ng 4 cha HC1.

2HC1 + Na2C03 2NaCl + C02t + H20

Vy ng 1 cha FCl2 v ng 2cha NH4HCO3.

32. a) C cc ion Na+, Al3+, Mg2+ trong cng mt dung dch. Lm th

tch ring bit chng khi nhau. Vit cc phng trinh phn ng ho hcxy ra khi tch.

b) C ba cht rn mu trng sa: Na2C03, MgC03, BaC03. Lm th no c th phn bit c chng.

HNG D N GII

a) - Cho hn hp dng dch tc dng vi dung dch NH3: Mg2AI3+s kt ta di dng hiroxit:

M g2* + 2NH4OH > Mg(OH)2 + 2NH4+



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31/179

AI3*. + 3NH4OH ---- > AI(OH)3i + 3NKU+

Lc, ra kt ta, phn nc lc cha Na* v NH4+ c c cn phn hu N4+ thnh NH3 bay i, phn rn cn l ho tan trongnc ta dc dung dch cha Na+.

- Phn kt ta cho tc dng vi NaOH d, Al(OH)3 tan cnMg(OH)2khng tan.

Al(OH)s + NaOH---- >NaAIOz.+ 2H20

Lc, ra ly kt ta, ho tan trong H+c dung dch cha Mg2+

Mg(OH)s + 2H+ > Mg2" + 2H20

- Sc kh CO2 vo phn nc lc, thu c Al(OH)3 kt ta honton:

NaAlOa + C 02+ 2H20 ---- >AI(OH)3l + NaHC03

Lc ly kt ta, ho tan trong H+c dung ch cha A3+

Al(OH)s + 3H+---- AI3+ + 3H2.0

b) Cht no tan c trong nc l NasCOa.

Phn bit BaC03 v MgC3 bng cch cho tc dng vi H2SO4lng. Cht no phn ng cho dung dch trong sut l MgC3, cht

no cho kt ta trng BaS04 l BaC3 (hc sinhvit phng trnhphn ng).

33. a) Dng mt ho cht phn bit cc dung dch K2SO4, K2C 03j K2S0 3>

K2S, K2SO3.

b) Cho 5 oxi kim loi sau ng trong 5 i mt nhn CuO, FeO, Fe20 3,Fe30 4 v Ag20; bng phn ng ho hc, hy dng cc ho cht cn thit nhn bit tng oxit kim loi ni trn.

HNG DN GI

a) Ly mi ng nghim mt t dung dch ri nh t t dung dchHC1 vo thy cc hin tng:

- ng khng c hin tng gi: K2SO4.

ng c kt ta keo: K2S1O3.

K2SO3 + 2H C1 -----> 2KC1 + H2SO3

- Ba ng c kh thot ra:



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32/179

+ Kh c mi trng thi: K2S

K2S + 2HC1----->2KC1 + H2s t (mi trng thi)

+Kh c mi hc kh chu: K2SO3

K2SO3+ 2HC1 ---- > 2KC1 + H2O + SO2T (mi hc)

+ Kh khng c mi: K2CO3K2C03+ 2HC1 ---- > 2KC1 + H20 + C02 (khng mi)

b) Cho 5 oxit kim loi vo 5 ng nghim khc nhau. dung dcHC1 vo 5 ng nghim th:

- ng c kt ta trng l Ag2.

AgsO + 2HC1 ---- > 2AgCli + H2O

- Ong c mu xanh lam l CuO.

CuO + 2HC1 * CuCl2 + H20

- Ba ng cn li l dung dch ca cc mui clorua st.

FeO + 2HC1 + FeC2+ H20

Fe203+ 6HC1 ---- > 2FeCl3+ 3H20

Fe30 4,+ 8HC1 ---- > FeCl2+ 2FeCl3+ 4H20

/ Sau dng dung dch NaOH cho vo 3 ng nghim c cha muclorua st:

- ng nghim xut hin mu trng xanh ri t t chuyn sannu l FeO.

FeCl2+ 2NaOH > Fe(OH)2 + 2NaCl .

4Fe(OH)2+ O2+ 2 H2O ---- > 4Fe{OH)3i

Hai oxit Fe203, Fe30 4 cn li phn bit bng cch cho tc dnvi HNO3, oxit no cho kh b ho nu ngoi khng kh l Fe304-

3Fe304+ 28HNO3 - >9Fe(N03)3 + NO + 14H20

2NO + O2 ---- >2N0 2

Cn li l oxit st (III) Fe20 3.

34. C 5 l mt nhn A, B, c , D, E cha cc dung dch HCI, H2BaCI2, NaCl, Na2C03. Xc nh cht cha trong mi l. Gii thch n bit:



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33/179

- cht trong l A vo cht trong B th c kt ta.

- cht trong ] A vo cht trong i c th c kh bay ra.

- cht trong l B vo cht trng l D th c kt ta.

H NG D N GII

Cht trong l B c kh ring to kt ta vi 2cht trong l A vD th B l BaCl2. Cht trong lo A to kt ta vi cht trong l B vto kh vi cht trong l c th cht trong l. lN2C3 vchttrong l D l H2SO4, cht trong l c l HC1.

Na2C03+ 2HC1---- >2NaCl + C02T + H20

35. C 4 t mt nhn c nh s t 1 n 4 cha cc dung dch

AgN03, ZnCI2, HCl, Na2C03. Bit cht trong l 2 to kh vi cht trong l 3nhng khng phn ng vi cht trong l 4 Xc nh cht cha trong mi l,

gii thch.

H NG D N

Cht trong l 2 to kh vi cht trong l 3 v khng phn ng vicht trong l 4nn cht trng i 2 l HC1, cht trong l 3 l Na2C3,cht trong l 4 l ZnCl2, cht trong l 1 l AgN03 (hc sinh t vitcc phng trnh phn ng minh ho).

36. C 4 cc cha ring bt: nc nguyn Chat, nc cng tm thi, nc

cng vnh cu, nc cng ton phn: Bng phng php ho hc hy xc nhloi nc no cha trong mi cc?

H NG DN GII

un nng mi cc, c hai nhm:

- Nhm A: Hai cc khng to kt ta l hai cc cha nc nguyncht v nc cng vnh cu.

- Nhm B: Hai cc u to kt ta l hai cc cha nc cng tam

thi v nc cng ton phn.Ca(HC03)2tU > CaCOsi +. C0 2 + H20

Mg(HC0 3)2 > M gC03>l + C 02t + H20

Nhn bit hai cc ca nhm A: Cho dung dch Na2C03 vo micc, cc n c kt t l cc cha nc vnh, cu, cc. cn li l ncnguyn cht.

3. NB & rcc A 33



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34/179

Ca2++ CO32" ---- >CaC034

Mg2* + CO32- >M gCO si

Nhn bit hai cc cua nhm B: Ch dung dch Na2CC>3 vo phnnc lc ca hai cc, n cc c kt ta th cc cha nc cng ton

phn, cc kia cha nc cng tm th.

37. C 4 ch bt mu trng tng t nhau l NaCi, ACI3j. MgC03, BaC03Ch c dng nc v cc thit b cn thit (l nung, bnh in phn ...). Hytrnh by cch nhn bit tng cht trn.

HNG D N GI I

by tng lng mui th nghim

- Ho tan vo nc, tch thnh hai nhm:+ Nhm A: tan trong nc l NaCl v AICI3

+ Nhm B: khng tan trong nc l MgC03j BaC03.

- in phn dung dch mui , nhm A (c, mng ngn)

2NCl + 2H20 dpi - > 2NaOH + cigt + Hat

2AICI3 + 6H2O j g l > 2Al(OH)3 + 3Clst + 3H2.t

Khi kt thc in phn, " vng catot ca bnh in phn no ckt ta keo xut hin bnh cha ACI3, bnh-kia l NaCl.

- Thc hin phn ng t sn phm in phn:

H2+ Cl2 > 2HC1

Ho tan nhm B vo dung dch HC1:

MgC0 3 + 2HC1 > MgCl2 + C0 2t + H20

BaCOs + 2HC1 > BaCl2+ c 2t + H20

Dng dung dch NaOH phn bit 2 mui MgCl2v BaCl2, t su ra BaC3v MgC03.

MgC2+ 2NaOH + Mg(OH)2i + 2NaCl

BaGl2+ 2NaOH > Ba(OH)2+ 2NaCl

38. C 3 l mt nhn cha cc dung dch, l X gm NaHC03v K2CO3 , lY gm KHCO3 v Na2S04, l z gm Na2G3 v K2SO4. Nu cch nhn bitcc l, nu ch dng dung dch BaCI2v dung dch HCi.



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35/179

HNG DN GII

Cch : Ly tng lng nh dung dch X, Y, z ra th.

Cho axit HC1 d vo 3 dung dch, lc nh phn ng xy ra

hon ton. Nh tip dung dch BaC2vo tng dung dch va thu c, dung dch no thy khng c kt ta l duhg dch X. Cn ha i dungdch Y, z c kt ta BaS04xut hin.

NaHCOg + HC1 ----->NaCl + C0 2T + H 20

K2CO3 + 2H C1-----> 2KC1+ C0 2T + H 20

Trong dung dch Y, z c ion S042- nn phn ng vi BaCl2:

S042- + BaCls---->BaS04i + 2Cr

- Cho dung ch BaCl2 .d vo 2 dng dch C1 li (Y, Z) lc lyly nc lc, cho axt HC1 vo. phn nc lc no thy c kh thotra, l nc lc t dung dch Y (KHCO3 + Na2S04) cn li l dungdch z.

dung dch Y: Na2S4+ BC2 ---- >BaS04-i- + 2NaCl

Trong nc lc gm KHCO3 v NaCl

KHCO3+ HC I---->KC1 + C02T + H20

dung dch Z: K2SO4 + BaCl2 ---- >BaS04>i + 2KC1

Trong nc lc ch c KC1 v NaCl.

Cch 2:Cho BaCl2 (d) vo 3 ng nghim cha 3 dung dch X, Y,z, lc tch kt ta thu c kt ta Xi, Yi, Zi v 3 dung dch nc lcX2, Y2, Z2. Cho dung dch HC1 vo mi kt ta v mi dung dch nc

lc ta c kt qu nh sau: Nu t kt ta v t nc lc u c kh thot ra th suy ra dung

dch ban u l dung dch X.

BaCl2+ 2NaHC03^ Ba(HC03)2+ 2NaCl (X2) +HC1 [C 02 T

[BaCOg (Xj) > [C 02 T

Na2S04+. BaCla---- >BaS04l + 2NaC

lc



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36/179

Nu t kt ta khng c kh thot ra nhng t nc lc c kthot ra th suy ra dung dch ban u l Y.

KHCO3 ,BaCi,d |K H C 0 3j Ba(HC0 3)2 (Y3)N a2S04 * [BaS04 (Yj)

+HC1 |C 0 2 t|BaS04khng tan

Nu t kt ta c kh thot ra v c kt ta khng tan tronHC1 d v t nc lc khng c kh thot ra th suy ra dung dch bu l dung dch z.

|N a 2C03 +BaCl2d |BaCl2 +HC1I K2S04 ^ [BaCOg , BaS04 *

j khng c hin tng gC kh C02v BaS04 khng tan

(Hc sinh vit cc phng trnh phn ng minh ho).

39. a) Cho 4 dung dch sau: (NH4)2S 0 4, NH4NC>3, FeS04, AIC!3. Hmt kim loi nhn ra cc dung dch trn.

b) C 3 ung dch mt nhn c nh s 1,11, IUcha cc cht sau: HC

K3

P 04i BaCI2. (- Nu cc [ vo cc II khng c hin tng g xy ra, nu cc

vo hn hp thu c cng khng c hin tng g xy ra.

- Nu cc l vo cc tll khng c hin tng g xy ra. Nu cvo hn hp thu c cng khng c hin g xy ra.

Xc nh cc no ng HCI.

HNG D N GI

a) Dng kim loi Ba cho vo cc dung dch mu i v u xphn ng

Ba + 2H2O >Ba(OH)2+ H2T

- mt dung dch to ra kt ta, ng thi c mi khai thot r l dung dch (NH^SCV

- mt dung dch ch thy c mi khai thot ra l dung dcNH4NO3.



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37/179


38/179

; HNG D N GI I

a) Cho vo mi ng nghim cha cc axit trn mt ming ngnu ng nghim no e kh mu nu thot ra thi l HNO3 c.

Cu + 4HNO3 ---- >Cu(NOs)2+ 2N02t + 2H20

Nu ng nghim no thot ra kh c mi hc, to thnh dundch mu xanh l H2SO4 c.

Cu + 2H2SO4 -> CuS0 4+ S02T + 2H20

Cho vo hai ng nghim cn li mt lng AgN03, ng nghimno to kt ta trng l HC1, to kt ta mu vng l H3PO4.

HC1 + AgN03> HNO3+ AgCl-i (trng)

H3PO4+ 3AgNC>3---- >3 HNO3+ Ag3P0 4l (vng)

b) - Cho Ba(CH3COO)2 tc dng vi dung dch axit, ban u ckt ta trng,nhn c dung dch H2SO4

Ba(CH3COO)2+ H2S04 ---- >BaS0 4v + 2 CH3COOH

- Lc ly kt ta, cho AgN3 tc diig vi dung dch nc lc, ckt ta trng, nhn ra HC1.

AgNOs + HC1-----> + H N 0 3- Cho Cu vo dung dch ban u, un. nng c kh mu n tho

ra, nhn ra c HNO3.

3 Cu + 8HNO 3----- 3 Cu(N0 3)2 + 2N 0 + 4 H 20

2NO + 0 2 ---- >2N02t

41. C 5 l ng kh ring bit cc kh sau:

a) 0 2l Cl2, HCi, 0 3, S0 2.b) N2, Hg, CI, Fg, CO2.

Lm th' no nhn bit tng kh.

HNG D N GII

a) Kh Cl2c mu vng lc.

Dng giy tm h tinh bt v dung dch KI nhn bit c 0 3:

Os + 2KI + HsO---- 0 2 + I2+ 2KOH



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39/179

I2lm h tinh bt chuyn mu xanh.

Dng qti tm thm nc nhn bit c kh HC1 v SO2- Cn lil kh 0 2.

Phn bit l kh HC1 v SO2bng dung dch nc brom. SO2 lmmt mu dung dch brom theo phng trnh phn ng:

S02+'Br2+ 2 H20 ---- >2HBr + H2SO4

b) Kh Cl2mu vng lc, kh F2mu lc nht.

Dng dung dch Ca(OH>2 nhn bit CO2.

t trong khng kh d nhn ra kh H2: 2 H2+ 0 2 ---- >2H2O (hi)

Cn li l kh N2-42. Nhn bit cc kh sau cha trong cc l ring bit bng phng php

ho hc: 0 2l O3 , N2, Cl2, NH3.

HNG DN GII

Ly mi cht mt t em th nghim. Dng giy qu m cho vo 5mu cha kh.

- C 1 kh lm qu tm ho xanh l NH3.

- C 1kh lm qu tm ho sau mt mu l kh Cl2.

Cl2 + H20 * HC1 + HCIO

Dng giy c tm dung dch KI v h tinh bt vo 3 kh cn li,c mt kh lm giy ho xanh l 0 3-

2KI + 0 3 + H 20 -----> 2KOH + I2 + 0 2

I2lm h tinh bt chuyn mu xanh'.

Hai kh cn li a que dim cn m vo, que dim chymnh nhn ra kh 0 2, que dim tt dn nhn ra kh N2.

43. C 6 bnh ng cc kh N2, H2l C02l co, Cl2, 0 2. Hy nhn bit cc

kh trong bnh bng phng php ho hc.

HNG D N GII

- Dng dung dch hn hp (K + h tinh bt) th, ch c clophn ig:

C2+ 2 K I ---- 2KC1 + (lm xanh h tinh bt)



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Do , bnh ng kh lm xanh dung ch hn hp l kh clo.

- Dng nc vi trong th 5 bnh kh cn li, ch c C02 phng theo phng trnh phn.ng sau:

C()2+ Ca(OH)2 ---- >CaCOg + H20

CaCOs + C02+ H20 ---- >Ca(HC03)2Do , bnh cha cha kh lm c nc vi trong, sau tr l

trong sut l kh C2-

- Dng bt Cu mu th 4 kh cn li, ch c 0 2phn ng:

2 Cu + O2 > 2 CuO (mu en)

Do , kh chuyn bt ng t mu sang en khi un nng lkh oxi.

- I)ng CuO th 3 kh cn li th:

CuO + H2 > H2O + Cu (mu d)

CuO + CO ^ > CO? + Cu (mu )

Kh chuyn c bt CuO mu en thnh , bt Cu m v khsinh ra khng lm c nc vi trong l kh H2.

Kh chuyn c bt CuO mu en thnh bt Cu mu v khsinh ra m c nc vi trong l kh co.

- Kh cn li l N2.

44. Dung dch A cha cc ion Na+, NH4+, HCO3", CO32" v S 0 42~. Cqu m v cc dung dch HC, Ba(OH)2 c th nhn bit c cc ion ntrong dung dch A.

H NG DN GI

C th nhn bit t t c cc ion tr ion Na+.

iu ch BaCl2nh ch th ca qu tim:

2HC1 + Ba(OH)2 ---- >BaCl2+ 2HzO

Cho dung ch BaC.2d vo dung dch A ta thu c kt ta B vdung dch X. '

Ba2++ S042----->BaS04i

40



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41/179

Ba2+ + C032----- BaCQsi

Ho tan B trong dung dch HC1 d thy c kh bay'ra (nhn bitc CO32) v mt phn khng tan (nhn bit dc S042-).

Cho ung dch X tc dng vi dung dch HCI thy c kh bay ra(nhn bit c HCCV):

H++ HCO3' ---- >C02t + H20

Ly dung dch A cho tc dng vi dung dch Ba(OH)2 c kh mikhai bay ra (nhn bit ion NH4+):

. NH 4+ + O H "----->NH3T + H20 .

45. a) Lm th.no phn bit c hai kh 0 2v 03 hai bnh mt nhn.

b) C 3 mu phn ho hc khngIghi nhn l phn m NH4NO3, phn

kali KCI v phn supephotphat Ca(H2P0 4)2 . Hy nhn bit mi mu phn bntrn bng phng php ho hc.

HNG DN GI

a) Cho hai kh qua dung dch KI, kh no lm dang dch t khngmu chuyn sang mu vng nu l kh 0 3:

0 3 + 2KJ + H20 V I 2 + 0 2 + 2KOH

b) Ch dung dch NaOH vo 3 ng nghim cha 3 mu phn ho

hc trn v un nh, ng nghim no c mui khai l NH4NO3, 2 ngnghim cn li khng phn ng.

NH4NO3 + N aO H NH3T + NaNOa + H20

Cho Ca(OH)2 vo 2 ng nghim cn li, ng nghim no cho ktta trng l Cad2P0 4)2cn ng nghim khng phn ng l KCl.

Ca(H2P04)2+ 2 Ca(OH)2 > Ca3(P 04)2i + 4H20

46. C 3 l ng 3 dung ch HCI, HN03, H2SO4. dy trnh by phng

php ho hc d bit cc l ng durig dch axit trn.

HNG D N G

Cho dung dch BaCls vo cc ng nghim cha 3 axit trn. Ongnghim no cho kt ta trng l H2SO4.

Sau d cho dung dch AgN03 vo hai ng nghim cn li, ngnghim no cho kt -ta trng l HC1. ng -nghim khng c hintng xy ra l HNO3 (hc sinh 'vit phng trnh phn ng).

41



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O

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47. C 3 l cha cc dung dch HCI, H2S 0 3, H2SO4 mt nhn. Hydng mt ho cht nhn bit 3 axit cha trong cc l.

HN G D N GI I

Cho3 mu th ln lt tc dng vi Ba(OH)2. Hai mu th chokt ta trng l H2SO3 v H2SO4.

H2SO3+ Ba(OH)2- ^ BaS03 + 2 H2O

H2S04+ Ba(OH)2 ---- >BaSCU + 2H20

Mu th cn l khng c kt ta l HC1

Ly hai kt ta cho tc dng vi dung dch HC1, kt ta no tav c kh by ln l BaS03v suy ngc l H2SO3. BaS04khng tan.

BaSOs + 2HC1---- >BaCl2+ S02t + H20 -BaS0 4+ HC1 * khng phn ng

48. a) C 5 binh kh: N2, 0 2, C0 2 , H2v OH4. Hy trnh by phng phpho hc nhn bit tng kh

b) Trong mt bnh cha hn hp kh: CO, CO2, SO3, S 02 v H2. Trnh byphng php ho hc nhn bit tng kh.

HNG D N GI

a) - Cho tng bnh kh trn qua nc vi trong d, kh no chokt ta trng l kh C02.

CO2+ Cct(OH)2---- > CaC03 + H2O

- Cho que dim cn m vo cc bnh kh cn li,khbng1chy l kh O2-

- t cc kh cn li, c 2 kh chy c, kh no cho sn phm

chy qua nc vi trong to kt ta trng kh l CH4. Kh chy cnli l H2- Kh khng chy l N2 (N2 khng chy nhit di2000C).

b) Cho hn hp kh qua dung dch BaC2, nu c kt ta mutrng BaS04, kh trong hn hp c SO3.

SO3 + H2O ----- H2SO4

H2S04+ BaCl2 ---- >BaS0 4 + 2HC1



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43/179

- Cho hn hp kh cn li qua dung dch nc brom, nu -dungch brom b mt mu, kh trong hn hp c SO2.

SO2 + Br2+ 2 H2O ---- >H2SO4+ 2HBr

- Cho hn hp kh sau khi qua dung ch nc brom, qua dungdch Ca(OH)2 d, cho kt ta mu trng, chng t trong hn hp ckh CO2-

CO2+ Ca(OH)2 ---- ^ C3.C03 'l' + H2O

- t chy hn hp kh cn li (CO v H2) nu c hi nc, chngt hn hp kh ban u c H2- Kh sau khi t cho qua dung dch ncvi trong d, nu c kt ta trng, chng t trong hn hp kh c co.Hoc c th lm nh sau:

Cho hn hp kh cn li (CO v H2) sc vo bnh cha dung dchPdCl2 d, thy dung ch b sm mu, chng t trong hn hp c khCO (mu sm do to Pd).

CO + H20 + PdCl2 > P d i + C02+ 2HC1

Kh cn dn qua ng cha CuO nung nng, thy xut hin Cumu , chng t c kh hiro.

H2+ CuO - > H20 + Cu (mu )

49. Dng mt kim loi, hy phn bit cc dung dch axit HCI, HNO3,H2S04 v H3PO4. Vit phng trnh phn ng minh ho.

HNG DN GI

Dng kim loi B, cho tc dng vi cc dung dch axit.

Axit gii phng kh mu nu khi un nng l HNO3

Ba + 4 HNO3 > Ba(N03)z + 2N0 2t + 2H20

Axit phn ng cho kh bay ra, khng to kt ta l HCI, hai axitphn ng to kt ta l H2SO4 v H3PO4.

Ba + H2SO4 ---- >BaS04 + H2T

3Ba + 2H3PO4>Ba3(P0 4)2 + 3H2T

Cho dung dch HC1 vo hai kt ta trn, kt ta khng tan lBaS04 suy ra axit bn du H2SO4, kt ta tan l Ba3(P04)2, axit banu l H3PO4.

Ba3(P0 4)2+ 6HC1 3BaCl2 + 2H3PO4



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50. Lm th no nhn ra s c mt ca mi kh trong hn hpCO, C02, SO3bng phng php ho hc. Vit cc phng trnh phn ng.

HNG DN GI I

Dn hn hp kh qua dng ch BaCl-a, nu c kt tua trng thnhn c SO3:

SO3 + H2O + BaCl2 --->2HC1 + BaS04^ (trng)Tip tc dn hai kh cn li qua, nc vi trong d, nu vn

th nhn ra c kh COg:

CO2+ Ca(OH)2- >H2O + CaC03-i (trng)

Kh cn li khng b hp th em dn qua CuO nungnng thy:

CuO + CO -> Cu 4- cc>2(mu en) (mu )

Hp th sn phm kh bng nc vi trong d, nu vn c sura kh ban u l GO.

CH 3

Tch cc kim loi, phi kim v hp cht ca chng ra khi hn hp

51. a) C hn hp cha AI, Fe, Mg. Hy trnh by phng php hotch ring tng kim loi ra khi hn hp.

b) Hy dng phng php ho hc tch cc cht trong hn hpFe20 3, CaC03. Vit cc phng trnh phn ng.

HN G DN GI

a) So' tch 3 kim loi:

AIFe

Mg

+C02+H20 t" pncNaAI02 . A1(0 H)3 -*A1203 a i_ +HC _ +NaOH _ _ t"Fe,Mg - FeCl2, MgCl2 Fe(OH)2,Mg(OH)2 -*Fe203 ,Mg0

, +coe H2SO4 c ngui

pnc +8aCl2 r


45/179

b) - Cho hn hp AI2O3, Fe23, CaC03 tc dng vi dung dchNaOH, AI2O3 tan lc ta c dung dch nc lc l NaAlO, phnkhng tan l Fe203v CaC03-

AI2O3+2NaOH^ 2NaA102+ H20

Sc kh C02vo dung dch nc lc:

NaAIOs + C02+ 2HsO AKOHDsi + NaHCOs

21(0H)3 > A1203+ 3H20

- Nhit phn Fe23v CaC03

CaC03 ) CaO + H20Cho hn hp Fe203 v CO ho tari vo nc, CaO tan, lc ta

ic Fe203 - Cho kh C02yo dung dch nc lc:

' . CaO + HO Ca(OH)2

Ca(OH)2+ CO2 > CaC03+ H20

Lc ta c CaC03.

52. a) C dung dch FeS04ln p cht l C11SO4. Lm th no li btp cht bng phng php ho hc.

b) Nu bc c ln tp cht nhng kim loi km, thic, ch, bng cchno c th loi nhng tp cht? Vit cc phong trnh phn ng.

HNG D N GII

a) Ta cho bt st (d) vo dung dch hn hp, Fe s kh ht ionCu2+thnh Cu

Fe + C11SO4 - > F0SO4 + Cu

Sau lc, loi b phn cht rn khng tan, nc lc l ung dchFeS04 tinh khit.

b) Ngm kim loi bc c ln tp cht trn vo dung dch AgN03d. Ion Ag+s oxi ho nhng kim loi trong tp cht thnh nhng iontng ng tan vo dung dch. Sau lc, ta c Ag tinh khit (hcsinh t vit cc phng trnh phn ng).

53. C mt hn hp bt cc kim loi bc v ng. Hy trnh by phngphp ho hc tch ring c kim loi bc v ng. Vit cc phng trnhphn ng.



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HNG D N GI I

Cch 1: Ngm hn hp bt kim loi Ag v Cu trong dung dchAgNC>3va hoc d. Cu s kh ion Ag* thnh Ag v lng Cu tronghn hp b oxi ho thnh Cu2+. Lc dung dch ta c Ag.

Cu + 2AgN03 ---- >Cu(N03)2+ Agi

Nc lc l dung dch Cu(N0 3)2 nu lng AgNC>3 dng va nu dng d AgN3 th nc lc c thm AgN03, ta ngm l ngtrong dng dch ny Cu kh ht ion g+thnh g bm trn l CuDung dch cn li ch c Cu(N0 3)2. in phn dg dch ny vi incc tr, ta thu c Cu catot.

2Cu(N03)2 + 2H20 dp- > 2Cu + 0 2t + 4HNO3

Hoc c th chuyn Cu(N03)2theo s chuyn ho sau:

Cu(NOs)2 *Na0H- > Cu(0 H)2 - -*"-> Cu Cu

Cch 2:t hn hp Ag v Cu, Cu tc dng vi 0 2thnh CuO, Agkhng tc dng, cho hn hp sau khi t chy tc dng vi dung dchHC1, Ag khng tc dng, lc ta dc Ag. in phn dung dch nc lcta c Cu.

2C + 02 >2CuO

CuO + 2HC 1-----> C u C12 + H 20

in phn dng dch CuCl2

CuCl2 - - > Cu + C2

54. C hn hp A gm (Mg v Fe) vo dung dch B gm Cu(N0

AgN03 lc u cho n phn ng xong thu c hn hp rn c gm 3 kim lo

v dung dch p gm 2 mui. Hy trinh by cch tch tng kim loi trong hnhp c v tng mui ra khi dung dch D.

. HNG D N GII

Khi cho hn hp. (Mg, Fe) vo dung dch cha (Cu(N03)2, AgN03cho n phn ng xong, tu theo quan h v s mol ca tng kim lov tng mui m kt qu cui cng sau nhiu phn ng s khc nhauThe d kin cho sau phn ng thu c hn hp 3 kim loi vdang dch gm 2mui nn ta c nhn xt:



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47/179

Hai mui trong dung dch khng th l mui ca kim loi ngsau cc kim loi trong hn hp 3 kim loi. Nn c th xy ra cc phnng sau:

Mg + 2AgN03---

>Mg(N03)2 + 2Agi (1 )Mg + Cu(N03}2 >Mg(N03)2+ C u (2)

Fe + "CuNOs^--- ^ Fe(N03>2 + Cii'i' (3)

Sau phn ng (3) cn d Fe nn hn hp rn c gm 3 kim loiAg, Cu, Fe v dung ch B gm Mg(N03)2v Fe(N03)2,

Hoc: Mg + 2AgN0 3 >Mg(N0 3)2 + A g l

Fe + 2AgN03 ---- Fe(N03)2+ 2Ag

+ Cu(N3)2 -----^ F(N03)2 +CuJ'Sau phn ng (3) cn d Fe v kt qu nh trn,

a) Tch hn hp Ag,Cu, Fe

S tch:

Ag

Cu

Fe-

+NaOH- F6OI2

+HC1lc

_ +02 t +H2Fe(OH)2 -> Fe(OH)3 Fe203 Fe

Agt trong

khng kh

CuOi+HC1

'Ag

Cui Ag J ic

(Hc sinh vit cc phng trinh phn ng)

b) Tch dung dch Mg(N03)2v Fe(N03)2

Hn hp dung dch:

Mg(N03)2 Fe - >Pe(NO?AFe(N03 )2J ** (Mg(N03)2

_ dpCuCls -> Cu

55. Trinh by cch tch ri tng cht sau y. ra khi hn hp cht rn vvit y cc phng trnh phn ng ho hc xy ra: AICI3l FeCJ3, BaCI2.

HNG D N GII

AICI3

FeCls

BaCl

+ NaOH d, lcNaA102 ,BaCL>

+HC1Fe(OH), - FeCL



B

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48/179

+HC1NaA102 +co c jAI(OH)g > A1C13(c cn)

R a p l I * c cn2 J (BaCl2 -> BaCl2(rn)

Hc sinh vit cc phong trnh phn ng minh ho.

56. Trnh by phng php tch:a) Fe2 0 a ra khi hn hp Fe20 3 , AI2O3, S2dng bt.

b) Ag ra khi hn hp Ag, Cu, Fe drig bt

Vi mi trng ch dng duy nht mt dung dch cha mt ho cht lng oxit hoc km loi cn tch vn gi nguyn khi lng ban u. Vit cphng trnh phn ng v ghi r iu kin.

(Trch thi tuyn sinh Bi hc, Cao ng nm 2002, kh

HNG DN GII

a) Cho hn hp tc dng vi dung dch NaOH c, nng. Fe2khng tan, lc, tch ta c Fe203 . AI2O3v Sip2 tan do phn ng:

A1203+ 2NaOH---- 2NaA102+ H20

S0 +2NaOH + Na2Si03+ HzO

b) Cho hn hp tc dng vi dung dch mui st (III) d nFeC3, Fe2(S04)3..., Ag khng phn ng, lc tch c Ag. Kim long, st tan do phn ng:

Cu + 2FeCl3>2 K6CI2+ C11CI9 *

Fe + 2FeCls------- >SFeCl

57. Mt loi mui n b ln cc tp cht l Na2S 0 4, NaBr, MgCI2, CaCv CaS04. Hy trnh by phng php ho hc ly NaCI tinh khit.

H NG DN G

Ho tan hn hp mui trn vo nc th c dung dch hn hcc mui trn (CaS4c tan rt t trong dung dch).

a) Thm mt lng BaCl2 d vo dung dch loi ht ion SO4di dng BaS04kt ta.

b) Thm vo dung dch mt lng d Na2C03 loi ht cc ioCa2+, Mg2", Ba;:\

c) Thm mt lng kh Cl2vo dung dch Br2b y ra.

d) Thm mt lng tha HC1 tc dng ht vi ion CO32'.



B

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O

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e) C cn dung dch cn li thu c NaCl tinh khit.

58. Cho hn hp bt cc kim loi Cu, Fe, Ag, AL Hy dng phng phpho hc (k c in phn nu cn) tch ring tng kim loi ra khi hn hp.

HNG D N G1

- Tch AI: Ho tan hn hp trong NaOH d.

2A1 + 2NaOH + 2HsO > 2NaA102+ 3H2

Lc ta c dung dch nc lc. Sc kh C0 2 vo dung dch nclc ta c AI(OH)3. Phn khng tan l Fe, Cu, Ag.

NaAI02+ C02+ 2HzO ^ AICOHU + NaHCOs

2A1(0H)3 > AfeOa + 3HO

2AI2O3 ip ~ > 4A1+ 302

- Tch Fe: Ho tan hn hp Fe, Cu, Ag trong dung dch HC1 d,ch c st tc dng, lc ta c dung dch nc lc l FeCl2 v phnkhng tc dng l Cu, Ag.

Fe + 2HC1---- >FeC2+ H2

in phn ung ch ta c Fe:

FeCI2 dpdd > Fe + CI2

- Phn khng tan l Ag, Cu. Ta em dt hn hp Ag, Cu, Agkhiig tc dng vi oxi, Cu tc dng thnh CuO. Cho hn hp ny tcdng vi dung dch HC1, CuO tan, lc ta c Ag v dung dch nclc c C11CI2. in phn CuC2ta c Cu.

2Cu + O2 ---->2CuO

CuO + 2HC1 > CuCl2+ H2O

C11CI2 dpd- > Cu + Cl2

' 59. Bng phng php ho hc, hy trnh by cch tch cc cht: Al20 3lFe20 3, S i0 2ra khi hn hp ca chng.

HNG D N G

Cho hn hp tc dng vi dung dch HC1, Si02 khng tc dng,lc ta c S1O2 v dung dch nc lc. Cho dung dch NaOH d vodung dch nc lc, lc ta c Fe(OH)3kt ta v dung dch nc lcl NaA102.

NB A A



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50/179

F62O3+ 6HC1---- >2FeCl3+ 3 H2O

AI2O3+ 6HC1 - >2AICI3+ 3H20

FeGls + 3NaOH > Fe(OH)3i + 3NaCl

AlCls + 3NaOH---->Al(OH)34r + 3NaClA1(0H)3+ NaOH - NaA102+ 2H20

Nhit phn Fe(OH)3 sau dng c o kh Fe203, ta dc Fe.

2Fe(OH)s Fe203+ 3H20

F62O3 + 3 C O > 2F AKOHU + NaHCOs

2A1(0H)3 A1203+ 3H20

2AV* - W - > 4A2+3^

Lu : V S1O2 cng tan trong NaOH, nn khng cho hn hpngay t u tc dng vi NaOH v sau ny kh tch c S 1O2-

60. Mt hn hp gm AI2O3, CuO, Fe20 3 , dng phng php ho htch ring tng cht ra khi hn hp.

HNG DN GII

- Cho hn hp tc dng vi dung dch NaOH, ch c AI2Ophn ng:

AI2O3+ 2NaOH---- >2NaA102+ H20

Lc ly dung dch nc lc cha NaA2. Sc kh CO2 vo dung

dch nc lc thu c A1(0 H)3kt ta.NaA2+ C02+ 2H20 ---- >Al(OH)3i + NaHCOs

Nhit phn A1(0H)3 thu c AI2O3:

2AI(0H)s - > A1203+ 3H20

- Hn hp cn li l CuO v Fe203, ho tan hn hp vo axit HC1

CuO + 2HC1---- CuCl2+ H20



B

I

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N

GT

O

N

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L

-

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Fe203+ 6HC1---- 2 FeCl3 + 3H20

Dung dch cha hn hp mui CuC2 v FeC3 cho tc dng viNH3 d.

CuCla + 2NH4OH---- >Cu(OH)2 + 2NH4CI

Cu(OH)2+ 4NH3 ---- >[Cu(NH3)4](OH)2

FeCla + 3NH4OH >Fe(OH)3i + 3NH4CI

- Lc, tch c Fe(OH)3, nung ' nhit cao ta thu c Fe23-

2Fe(OH)3 > Fe203+ 3H20

Trung ho [Cu(NH3)4](OH)2bng HC1 va

[Cu(NH3)4](OH)2+ 6HC1---- >CuCl2 + 4NH4CI + 2H20

Sau cho tc dng vi NaOH d:

CuCl2+ 2NaOH >Cu(OH)2 + 2NaCl

Nung kt ta thu li CuO

Cu(OH')2 > CuO 4-H20

61. C hn hp ng bt gm 4 kim loi AI, Cu, Fe, Mg. Bng phngphp ho hc hy tch ring tng kim loi ra khi hn hp. Vit cc phngtrnh phn ng dng.

HNG DN Gl

- Cho dung dch NaOH d vo hn hp, tch c Al:

2AI + 2NOH + 2H20 ---- 2NaA102+ 3H2

Lc tch c 3 kim loi khng phn ng Fe, Cu, Mg.

- Sc kh CO2 vo phn nc lc thu c kt ta, nung kt ta,in phn nng chy thu c AI:

NaAlOa + C02+ 2H20 ---- * A](OH)3 + NaHCOa

2A1(0H)3 > A1203+ 3H20

2A2*q 3 n S S v > 4A1+ 30 2

- Cho 3 kim loi cn li vo dung dch HC1 d, tch c Cukhng phn ng v hai dung ch mui FeCJ2v MgC2, cho dung ch



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NaOH d vo 2 dung dch mui, thu c 2 kt ta Fe(OH)2 Mg(OH)2. Lc ly kt ta v nung nhit cao cho MgO v Fe20 3

- Thi CO vo hn hp 2 oxit nung nhit cao, MgO khphn ng, Fe203 phn ng cho Fe. Ho tan hn hp sau khi nung ( ngui) vo H 2 S O 4 c, ngui, Fe khng tan, MgO tan trong H2S

c. Lc ta c Fe v dung dch nc lc.- Cho dung dch NaOH d tc dng vi MgS04cho Mg(OH)2l, c

dung dch HC1 tch dng vi Mg(OH)2, in phn nng chy MgCthu c Mg.

Hc sinh t vit cc phng trnh phn ng trn.

62. Trinh by phng php ho hc tch ring tng kim loi rhn hp: CuO, MgO, AI2O3 (lng kim loi kh n g i a u khi tch ).

HNG DN GIIS tch ring tng kim loi:

CuCn

MgO

AI2O3

_fNaOHd_ ) Lcr ^

^ Al(OH), _ U .a ]203 ANaaAl G

22_,.Cu + MgO JS 5 U Lc, tch

Mg MgCl * . > Cu

63. Nu phng php tinh ch Cu trong mt mu qung Cu c ln F, A

v s.HNG DN GI

Ho tan mu qung trong dung dch HC1 d loi b Fe

Fe + 2HC1---- FeC2+ H2

t trong kh oxi loi b s, Ag khng tc dng vi oxi

2 C + O2 --- 2CuO

s + O2

^SO2Hn hp cht rn thu c l CuO v Ag, tch Ag ngi ta chhn hp cht rn tc dng vi dung dch axit HC1.

CuO + 2HC1----- C u C 12 + H20

Ag + C1---- >khng tc dng

Lc ta c Ag v ung dch nc lc l CuCl2



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CuCl2 + 2NaO H Cu(OH)2 + 2N aC l

: Cu(OH)2 t0 > CuO + H20

Cu O + H2 t0 -> C u+ H 20

64. a) Nu phng php tch hn hp kh Cl2 Ha v C 02thnh tng chtnguyn cht.

b) Nu phng php tch hn hp vi, vi sng, thch cao v mui nthnh tng cht nguyn cht.

HNG D N GI

a) Cho hn hp qua dung dch NaOH

Cl + 2NaOH > NaCl + NaClO + H20

C02+ 2NaOH---->Na2C03+ H2Q

Kh H2khng phn ng tch ring v lm kh.Thm axlt HG1 vo dung dch sau phn ng v thu y CO2 v

lm kh.Na2C03 4-2HC1---- >2NaCl + C02 + H20

Dung dch thu c em un nng:

2NaC10 ^ >2NaCl + O2

in phn c vch ngn dung dch NaCl:

2NaCl + 2H20 - > 2NaOH + H2t + Cl2tc vch ng n

b) Ho tan hn hp trong nc, vi sng tan:

CaO + H20 - Ca(OH)2

Lc, ta c cht khng tan l vi; thch cao v dung dchnc lc c NaCl v Ca(OH)2. Cho dung dch Na2C03d vo ung dchnc lc:

Na2C03+ Ca(OH)2 CaG03 + 2NaOH

Lc, ta c CaC3 v dung dch nc lc (gm NOH, NaCl vNa2C03d), nhit phn kt ta CaC03cho CO.

CaCOs fc0 -> CaO + C02 ;

Cho dung dch HI vo dng dch nc lc thu c NaCl:

NaOH + HC1 >NaCl + H20

Na2C03+ 2HC1 - > 2NaCl + C02 +'H 20 -



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Ra hn hp rn gm vi v thch cao, sau 'cho tc dngvi dung dch HC1, vi tc dng, thch cao khhg tc .dng, lc tac thch cao v dung dch nc lc. Cho dung dch Na2C3vo dungdch nc lc thu li vi.

CaCOs + 2HC1 '4CaCl2+ C02 + H20CaCl2+ Na2C03 ---- CaC03l+ 2NaCl

65. a) Trong phng th1 nghim bng phng php no c th tch kh N2v kh CO2ra khi hn hp kh gm N2, O2, c o , C 02) hi nc?

b) Mt hp kim c cha Cu, Fe, Ag, Au. Hy nu phng php tch Ag, ring Au t hp kim,trn.

HNG D N G I

a) Cho hn hp kh qua ng ng p trng (hp th 0 2)4P + 502 ---->2P2O5

Cho hn hp kh. cn li (CO, N2, C02, hoi nc) qua ng ngCuO un nng (CO phn ng).

CuO + CO - > Cu + COat"

Kh cn li (gm N2, C02, hi nc) qua bnh ng Ba(OH)2 d(hp th CO2):

C02+ Ba(OH)2- >BaC0 3>l + H20 Kh cn li (gm N2, hi nc) qua H2SO4 c (hp th nc) 'cnli l N2 Kt ta BaC03cho tc dng vi H2SO4:

BaCOs + H2SO4 >BaSG4 + C02t + H20

b) u tin ho tan hp kim bng dung dch HGI d loi Fe:

Fe + 2HC1- FeCl2+ H2T .

Lc thu Cu, Ag, Au em t ngoi khng kh s c CuO, Ag, Au.Dng dung dch HC1 ho tan CuO.

,2Cu + O2 >2CuOCuO +

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NHẬN BIẾT VÀ TÁCH CÁC CHẤT RA KHỎI HỖN HỢP (TÁI BẢN LẦN THỨ 5) - NGÔ NGỌC AN