For an electrochemical cell reaction
aA + bB → cC + dD
The Nernst’s equation for cell reaction is
The values of a, b, c, d and n can be obtained from the balanced cell reaction. (i) Anode reaction:
Cathode reaction:
Overall cell reaction:
Here, n= 2,
The Nernst equation for Ecell at 298 can be written as
For the given cell Anode reaction:
Sn(s) → Sn2+ (aq) + 2e–
Cathode reaction:
2H+(aq) + 2e– → H2(g)
Overall cell reaction:
Sn(s) + 2H+ (aq) → Sn2+(aq) + H2(g)
Here, n = 2, E°cell = E°cathode – E°anode = 0 – (– 0.14 V) = + 0.14 V.
The Nernst equation for Ecell and 298 k can be written as: