The standard reduction potential of Pb and Zn electrodes are – 0.126 and -0.763 volts respectively. The e.m.f of the cell
Zn|Zn2+(0.1M)||Pb2+(1M)|Pb is
>0.637 V
E=E∘−0.059nlogZn+2Pb+2E∘=E∘c−E∘a=−0.126−(−0.763)
⇒−0.126+0.763=0.637
⇒0.637−0.0592log0.11
=0.637−0.0592log(10−1)
=0.637−0.0592(−1)log10⇒0.637+0.0592×1=0.6374+0.0295
=0.6665
i.e. Answer (c) [>0.637]