Electrochemistry - Result Question 56
####58. An electrochemical cell is set up as: $Pt ; H_2$ (1atm) $|HCl(0.1 M)||CH_3 COOH(0.1 M)| H_2$ (1atm); Pt. The e.m.f of this cell will not be zero, because
[1995]
(a) the temperature is constant
(b) e.m.f depends on molarities of acids used
(c) acids used in two compartments are different
(d) $pH$ of $0.1 M HCl$ and $0.1 M CH_3 COOH$ is not same
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Solution:
- (d) For a concentration cell having different concentrations of ions.
$E=\frac{0.0591}{n} \log \frac{C_1}{C_2}$
If all the concentrations are identical then obviously the cell voltage is zero. But as the $pH$ of $0.1 M HCl$ (strong acid) & $pH$ of $0.1 M$ $CH_3 COOH$ (weak acid) is not same, therefore the cell voltage will not be zero.
