Question

Give the net ionic equations for the following:

a. AgCl + ZnCl2

b. PbCl2 + Hg2Cl2

c. Cd(NO3)2 + AgNO3

d. HCl + HNO3

e. Hg2(NO3)2 + Hg(NO3)2

Answer 1

Metals with more negative Eo displaces other metal ions from its solution as it has more tendency to get oxidised.

a) 2Ag+ +2e2Ag Eo=+0.79                                              (E0=reduction potential)

Zn2+ +2e Zn Eo=-0.76

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net ionic=2Ag+ + Zn2Ag +Zn2+

b) Pb2+ +2ePb Eo=-0.13

Hg2 ²⁺ +2e2Hg Eo=0.79

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net ionic Pb +Hg2 ²+ Pb2+ + Hg

c) Cd2+ +2eCd Eo=-0.40

2Ag+ +2e2Ag Eo=+0.79

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net ionic =Cd+2Ag+ Cd2+ +2Ag
d) Cl2+ 2e2Cl- Eo=1.36]* 3

NO3- + 4H+ 3eNO + 2H2O E0=0.96]*2

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net =6Cl- + 2NO +4H2O3Cl2 + 2NO3- + 8H+

e) Hg2 ²⁺ +2e2 Hg Eo=0.79

Hg2+ +2eHg Eo=0.85

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2Hg +Hg2+Hg2 2 + Hg