13.2a Developing a Redox table

the relative reactivity of metals can be used to determine which redox reactions are spontaneous

In all redox reactions, electrons aretransferred from a reducing agent(RA) to an oxidizing agent (OA)

list of elements in decreasing order of their reactivity, or ability to react chemically in aqueous solution

most active elements appear at the top of the table bottom right of ½ rxtn table

reactivity decreases as we move down the list decreases as we move up the right side of ½ rxtn

table under ordinary conditions each element in the

table can replace any element that appears below it above it on ½ rxtn table

Activity Series of Metals

a more active element displaces a less active element in a compound metals displace metals or H

Cu + 2 AgNO3 Cu(NO3)2 + 2 Ag

Mg + 2 HCl MgCl2 + H2

nonmetals displace nonmetals2 KI + Br2 2 KBr + I2

carbon displaces metals from oxides3 C + Fe2O3 3 CO + 2 Fe

always redox

Al + Zn(NO3)2 Al (NO3)3 + Zn

Aluminum is higher than zinc so it replaces zinc in the compound Zn(NO3)2

KBaSrCaNaMgAlMnZnCrFeCdCoNiSnPbHSbAsBiCuHgAgPdPtAu

displace H2

fromcoldH2O

fromsteam

fromacids

react

wit

h O

2 in t

he a

ir t

o m

ake

oxid

es

Fe is above Cu, so Cu metalwill not displace Fe2+

KBaSrCaNaMgAlMnZnCrFeCdCoNiSnPbHSbAsBiCuHgAgPdPtAu

displace H2

fromcoldH2O

fromsteam

fromacids

react

wit

h O

2 in t

he a

ir t

o m

ake

oxid

es

Gold is at thebottom, so it is

very unreactive.

KBaSrCaNaMgAlMnZnCrFeCdCoNiSnPbHSbAsBiCuHgAgPdPtAu

displace H2

fromcoldH2O

fromsteam

fromacids

react

wit

h O

2 in t

he a

ir t

o m

ake

oxid

es

Zn is above H,so Zn will react with acids

Zn + Fe2+ Fe + Zn2+

listing of metals by reactivity

free metal higher on the list displaces metal cation lower on the list

metals above H will dissolve in acid

Cu + Fe2+ no reactionZn + 2 H+ H2 + Zn2+

KBaSrCaNaMgAlMnZnCrFeCdCoNiSnPbHSbAsBiCuHgAgPdPtAu

displace H2

fromcoldH2O

fromsteam

fromacids

react

wit

h O

2 in t

he a

ir t

o m

ake

oxid

es

Fe is below Zn, so Zn metalwill displace Fe2+

Mg is aboveCu on theActivity Series

Mg will react with Cu2+ to form Mg2+

and Cu metal

but Cu will not react with Mg2+

Mg + H3PO4

Cu + H2SO4

Al + Fe2+

Predict whether the following will occur

Mg + H3PO4 Mg3(PO4)2 + H2

Cu + H2SO4 no reaction

Al + Fe2+ Al3+ + Fe

Sol’nSol’n

http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/redox/home.html

Predict whether the following will occur

Cu + HCl CuCl2 + H2

H2 + CuO H2O + Cu

Sol’nSol’n

Predict whether the following will occur

Cu + HCl CuCl2 + H2 no

H2 + CuO H2O + Cu yes

Textbook p571 #2-7 LSM 13.2C (top half)