Among the following metals,the strongest reducing agent is

Explain: Reduction reaction is possible with higher $E^{\theta}$ value.

The standard reduction potentials at $298 \ K$ for the following half reactions are given against each:
$Zn^{2+}(aq.) + 2e^- \rightleftharpoons Zn_{(s)}$; $E^\circ = -0.762 \ V$
$Cr^{3+}(aq.) + 3e^- \rightleftharpoons Cr_{(s)}$; $E^\circ = -0.740 \ V$
$2H^{+}(aq.) + 2e^- \rightleftharpoons H_{2(g)}$; $E^\circ = 0.00 \ V$
$Fe^{3+}(aq.) + e^- \rightleftharpoons Fe^{2+}(aq.)$; $E^\circ = 0.770 \ V$
Which is the strongest reducing agent?

Assertion : $Cu^{2+}$ ions get reduced more easily than $H^{+}$ ions.
Reason : Standard electrode potential of copper is $0.34 \ V$.

Which of the following expressions is correct for the standard Gibbs free energy change?

Calculate the $emf$ of the cell $Cu_{(s)} | Cu^{2+}_{(aq)} || Ag^+_{(aq)} | Ag_{(s)}$. Given: $E^0_{Cu^{2+}/Cu} = +0.34 \ V$,$E^0_{Ag^+/Ag} = +0.80 \ V$.