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Electrochemistry

Question
CBSEENCH12006128

Write the Nernst equation and calculate the emf of the following cell at 298 K:
Pt(s) | Br2 (l) Br– (0.01M) || H+ (0.03 M) | H2(g) (1 bar) | Pt(s)
Given E°Br2/Br– = + 1.08 V
Br/ Br

Solution
The net reaction is 2Br(aq) + 2H+(aq) → H2(g) + Br2(l)
The Nernst equation is
           Ecell = E°cell - 0.0592log1H+2 Br-2E°cell = 0-(+1.08) = 1.08
       Ecell = -1.08-0.0592log1[0.03]2 [0.01]2
            Ecell = -1.08 - 0.21Ecell = -1.29 V.