$A$ cell reaction is spontaneous when

Which among the following equations represents the reduction taking place in a lead accumulator at the positive electrode,while it is being used as a source of electrical energy?

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 $A$)?

The cell reaction $Cu + 2Ag^{+} \to Cu^{+2} + 2Ag$ is best represented by

Which of the following statements is $NOT$ correct for $H_2-O_2$ fuel cell?

Which of the following formulae is used to obtain the value of $E_{\text{cell}}^{\circ}$ for a reaction taking place in a Dry cell?