The reducing ability of the metals $K$,$Au$,$Zn$ and $Pb$ follows the order

Standard potential of electrode reaction $Cu^{2+}_{(aq)} + 2e^{-} \rightarrow Cu_{(s)}$ is $+0.34 \ V$. What is the standard potential of the reaction $2Cu_{(s)} \rightarrow 2Cu^{2+}_{(aq)} + 4e^{-}$?

Which of the following has been universally accepted as a reference electrode at all temperatures and has been assigned a value of zero volt?

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

The standard electrode potentials for some half-reactions are given below. Which statement is correct?
$(A) Sn^{4+} + 2e^{-} \rightarrow Sn^{2+}, E^o = +0.15 \ V$
$(B) 2Hg^{2+} + 2e^{-} \rightarrow Hg_{2}^{2+}, E^o = +0.92 \ V$
$(C) PbO_2 + 4H^{+} + 2e^{-} \rightarrow Pb^{2+} + 2H_2O, E^o = +1.45 \ V$

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