Which of the following will have a standard oxidation potential less than $SHE$?

Standard electrode potential of $SHE$ at $298 \, K$ is ............. $V$.

Among the following metals,the strongest reducing agent is

Given the standard electrode potentials: $E^o_{Cr^{3+}/Cr} = -0.74 \ V$,$E^o_{MnO_4^-/Mn^{2+}} = 1.51 \ V$,$E^o_{Cr_2O_7^{2-}/Cr^{3+}} = 1.33 \ V$,and $E^o_{Cl_2/Cl^-} = 1.36 \ V$. Based on this information,which is the strongest oxidizing agent?

The standard reduction potentials at $298 \ K$ for the following half-cell reactions are given below:
$Zn^{2+}_{(aq)} + 2e^{-} \rightleftharpoons Zn_{(s)} : -0.762 \ V$
$Cr^{3+}_{(aq)} + 3e^{-} \rightleftharpoons Cr_{(s)} : -0.74 \ V$
$2H^{+}_{(aq)} + 2e^{-} \rightleftharpoons H_{2(g)} : 0.00 \ V$
$Fe^{3+}_{(aq)} + e^{-} \rightleftharpoons Fe^{2+}_{(aq)} : 0.77 \ V$
Which one of the following is the strongest reducing agent?

The standard hydrogen electrode has a zero electrode potential because .....