Which statement is correct for a fuel cell?

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

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

Based on the following information,arrange four metals,$A$,$B$,$C$,and $D$,in order of increasing ability to act as reducing agents:
$(I)$ Only $C$ reacts with $0.10 \ M \ HCl$ to give $H_{2(g)}$.
$(II)$ When $A$ is added to a solution of the other metal ions,metallic $D$ is formed,but not $B$ or $C$.

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

Give the cell reaction and symbolic representation of the galvanic cell obtained by $E^o_{Ni^{2+}|Ni} = -0.23 \ V$ and $E^o_{Ag^{+}|Ag} = 0.80 \ V$.

Consider the figure and answer the following questions.
$(i)$ Cell $'A'$ has $E_{cell} = 2 \ V$ and cell $'B'$ has $E_{cell} = 1.1 \ V$. Which of the two cells,$'A'$ or $'B'$,will act as an electrolytic cell? Which electrode reactions will occur in this cell?
$(ii)$ If cell $'A'$ has $E_{cell} = 0.5 \ V$ and cell $'B'$ has $E_{cell} = 1.1 \ V$,then what will be the reaction at the anode and cathode?