Exercise 1 | Electrochemistry

Write the equations describing the electrode reactions and the net cell reaction for the following electrochemical cells:

Pt(s) | H2(g) | H+(aq) || Cd2+(aq) | Cd(s)

Pb(s) | PbSO4(s) | K2SO4(aq) | Hg2SO4(s) | Hg(l)

Pt(s) | H2(g) | H+(aq) || Cd2+(aq) | Cd(s):


H2 (g) → 2 H+ (aq) + 2 e-

Cd2+ (aq) + 2 e- → Cd (s)

Net cell reaction: H2 (g) + Cd2+ (aq) → 2 H+ (aq) + Cd (s)

 


Pb(s) | PbSO4(s) | K2SO4(aq) | Hg2SO4(s) | Hg(l):


Pb (s) + SO42- (aq) → PbSO4 (s) + 2 e-

Hg2SO4 (s) + 2 e- → Hg (l) + SO42- (aq)

Net cell reaction: Pb (s) + Hg2SO4 (s) → PbSO4 (s) + 2 Hg (l)