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

Standard reduction electrode potentials of three metals $A$,$B$,and $C$ are respectively $+0.5 \ V$,$-3.0 \ V$,and $-1.2 \ V$. The reducing powers of these metals are

$A$ galvanic cell with electrode potential of $A = + 2.23 \ V$ and $B = - 1.43 \ V$. The value of $E^o_{cell}$ is .............. $V$.

The standard reduction potentials for $Zn^{2+}/Zn$,$Ni^{2+}/Ni$,and $Fe^{2+}/Fe$ are $-0.76 \, V$,$-0.23 \, V$,and $-0.44 \, V$ respectively. For which of the following combinations will the reaction $X + Y^{2+} \rightarrow X^{2+} + Y$ be spontaneous?

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

Assertion : Copper reacts with $HCl$ and liberates hydrogen.
Reason : Hydrogen is present above $Cu$ in the reactivity series.