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XI - CHEMISTRYQUESTION PAPER 5

Max. Time: Three Hour Max. Mar! : "#$e%era& I% 'ru('io% :

). A&& *ue 'io% are (om+u& or,.

. Que 'io% %o. ) 'o are /er, hor' a% 0er *ue 'io% a%1 (arr, ) mar! ea(h.

2. Que 'io% %o. 3 'o ) are hor' a% 0er *ue 'io% a%1 (arr, mar! ea(h.

4. Que 'io% %o. )3 'o " are a& o hor' a% 0er *ue 'io% a%1 (arr, 2 mar!

ea(h.

5. Que 'io% %o. 'o 2# are &o% a% 0er *ue 'io% a%1 (arr, 5 mar! ea(h

6. U e &o 'a7&e i8 %e(e ar,9 u e o8 (a&(u&a'or i %o' a&&o0e1.

1. What happens when sodium metal is heated in free supply of air?2. Given:

Determine H for the reaction 2Al 2 O !s" #Al !s" $ O 2 !%".. &'plain why (eH 2 molecule has )ero dipole moment althou%h the (e* H

+onds are polar?#. ,redict the shape of the ,H molecule accordin% to - &,/ theory.

0. Which isotope of hydro%en is radioactive?. Write the correct 3,A4 name of the compound %iven +elow:

5. How many mono su+stituted derivatives of naphthalene are possi+le?

6. 7ame any two %ases responsi+le for %reenhouse effect.

8. Arran%e the followin% ions in order of increasin% ionic radius:9 $ , * 2*

4l *. Give reason.

1;. @mol 2 = 11#0 > @mol = #8;; > @mol # = 0;; > @mol 0 = 61;;

> @mol. nown

element is: a" 9 +" i c" 4a d" As. &'plain.

11.A sample of %as occupies .;; at 5 ; torr. 4alculate the volume the %as

will occupy if the pressure is chan%ed to 1.#0 atm and the temperatureremains constant.

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1 2:

2 .4onsider the reaction:

ndicate the direction in which the eEuili+rium will shift when:

!i" 4oncentration of O 2 is increased.

!ii" 4oncentration of O is increased.

!iii"

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4 and H in it.

ii" What will happen durin% assai%ne s test for nitro%en if the

compound also contains sulphur?

26.i" n a process 5;1 of heat is a+sor+ed +y a system and 8# of

wor> is done +y the system. What is the chan%e in internal ener%y

for the process?

ii"

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ii)

iii)

iv)

v)

Or

a) Convert benzene to

b) Convert to

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ANS ERS - QUESTION PAPER 5

1. On heatin% sodium in free supply of air it forms sodium pero'ide.

2 7a!s" $ O 2 !Air" 7a 2 O2

2. = 2 ' !$ !1 5;"" > @mol = $ #; > @ mol.

. (eH 2 is a linear molecule with H*(e*H +ond an%le as 16;K. Althou%h the

(e*H +onds are polar the +ond polarities cancel each other and the net

dipole moment is )ero.

#.

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7o. of moles of O = 6;@ 2 %@mol = 2.0 mol

Cole fraction of hydro%en

,artial pressure of hydro%en

ali metals have lar%e atomic si)e with only one valence electron.

metallic +ondin% +etween the atoms of the

metal (ecause of wea> metallic +ondin% al>ali metals are soft and

can +e cut with a >nife.

ii. /eactivity of metals depends on ioni)ation enthalpy. maller is the

ioni)ation enthalpy %reater is the reactivity. ,otassium has a lar%er

atomic si)e than sodium. aline earth metal

car+onate +ecause its ion +ein% lar%er in si)e is more sta+ili)ed +y

lar%er car+onate ion throu%h the formation of sta+le lattice.

1 . n i4l # i atom has empty d*or+itals in its valence shell.

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d or+itals of i can accept lone pair of electrons from water molecule.

&ventually this results in hydrolysis formin% silicon tetrachloride and

silicon hydro'ide.

4ar+on atom on the other hand does not have any vacant d*or+itals in itsvalence shell. Hence it cannot accept the electron pair from water

molecule.

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18.

******************* !1"

Accordin% to eEn !1"

1 mole of nitro%en %as reacts with moles of hydro%en %as

0.; ' 1; moles of hydro%en will %ive = 2@ ' 0 ' 1; moles of 7H

= . ' 1; moles of 7H

Cass of 7H produced = . ' 1; ' 15 % of 7H = 0 .1 >%

2;. i"

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& = 2.16 ' 1; *16 ! * "

ince & is ne%ative ener%y the freEuency of photon is %iven +y

21.

i. For n = 1

-alue of l = n Q 1 = 1 Q 1= ;

For each value of l

-alue of ml = * 1 ; $1

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ii. n 7F 7 atom involves sp hy+ridi)ation and one position is

occupied +y a lone pair. ward direction as the increase in temperature will +e

compensated +y a+sor+in% heat.

2#.

i.

9 + = L7H # $ M LOH*M@L7H#OHM

ii.

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ince solu+ility of 7i!OH" 2 is more than A%47 7i!OH" 2 is more solu+le

than A%47.

20.

tep 1 : Write the o'idation no.s and separate the reaction into o'idation

half and reduction half reactions

tep 2:

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ince the reaction ta>es place in acidic medium the +alancin% of

hydro%en atoms is done +y addin% the appropriate num+er of hydro%en

ions to the deficient side.

tep 0: Add the two reactions to %et the +alanced redo' reaction.

2 .

i.

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!ii" (lood red colouration due to Fe!47 "will +e produced.

26.

i. Heat a+sor+ed +y the system !E"= $ 5;1

Wor> done +y the system !w" = * 8#

4han%e in the internal ener%y ! 3" = E $ w = $ 5;1 $ ! * 8#"

= $ ;5

ii. G I = * 2. ; /< lo% 9

Or

u+stitutin% the values we %et

H I = * 12.856 >

u+stitutin% the values for G I = H I * < I we %et

G I = * 261 .2 .

ince the value of G I is ne%ative the reaction is spontaneous.

28.

i" (ora' solution on acidification forms +oric acid.

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ii" (F is tri%onal planar molecule. Due to p * p +ac> +ondin% lone

pair of electrons of F is +ac> donated to ( atom.

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Or

i"

ii"