$2H^{+} \, (aq) + 2e^- \to H_2 \, (g)$. The standard electrode potential for the above reaction is (in volts):

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

$A$ cell is constructed by dipping a copper rod in $1\,M\,CuSO_4$ solution and a nickel rod in $1\,M\,NiSO_4$ solution. The standard reduction potentials of copper and nickel electrodes are $+0.34\,V$ and $-0.25\,V$ respectively. Calculate the $EMF$ of the cell. (in $,V$)

The two half-cell reactions of an electrochemical cell are given as: $Ag^{+} + e^{-} \rightarrow Ag$; $E^{\circ}_{Ag^{+}/Ag} = 0.7995 \ V$ and $Fe^{2+} \rightarrow Fe^{3+} + e^{-}$; $E^{\circ}_{Fe^{3+}/Fe^{2+}} = 0.7710 \ V$. The value of cell $EMF$ will be: (in $V$)

Which reference electrode is used to measure the electrode potential of other electrodes?

Standard oxidation potentials $(SOP)$ of four metals $P, Q, R$ and $S$ are $+2.87 \ V, +3.05 \ V, -0.80 \ V$ and $+0.25 \ V$ respectively. The reducing power of these metals is: