Which colourless gas evolves,when $NH_4Cl$ reacts with zinc in a dry cell battery?

Which of the following is $NOT$ an example of a secondary voltaic cell?

The $Cu^{+}$ ion is not stable in aqueous solution. For the disproportionation reaction,what is the $E^o$ value in $V$? (Given: $E^o_{Cu^{2+} | Cu^{+}} = 0.15 \, V$; $E^o_{Cu^{2+} | Cu} = 0.34 \, V$)

In a fuel cell,$H_2$ and $O_2$ react to produce electricity. In this process,$H_2$ gas is oxidized at the anode and $O_2$ gas is reduced at the cathode. If $67.2 \ L$ of $H_2$ gas at $\text{STP}$ is consumed in $15 \ min$,what is the current produced (in $A$)?

Which of the following statements is correct regarding the cathode of an electrochemical cell?

Which of the following reactions is possible at the anode?