Which of the following mixtures is used as an electrolyte paste in a mercury cell?

Explain the different conditions when an external potential is applied in the opposite direction in a galvanic cell (Voltaic cell) by taking a suitable cell example.

If $\lambda_{m}^{o}(Br^{-}) = 78.1 \, S \, cm^{2} \, mol^{-1}$,calculate $\lambda_{m}^{o}(K^{+})$ using the following data:

Electrolyte	$\Lambda_{m}^{o} \, (S \, cm^{2} \, mol^{-1})$
$NaCl$	$126.5$
$NaBr$	$128.2$
$KCl$	$149.5$

$Zn_{(s)} | Zn_{(aq)}^{2+}(1 \ M) || Ni_{(aq)}^{2+}(1 \ M) | Ni_{(s)}$
Which is incorrect for the given cell?

Saturated solution of $KNO_3$ is used to make a 'salt-bridge' because:

Which of the following reactions occurs at the cathode of a common dry cell?