The standard reduction potentials of $2 \mathrm{H}^{+} / \mathrm{H}_2, \mathrm{Cu}^{2+} / \mathrm{Cu}$.…

The standard reduction potentials of $2 \mathrm{H}^{+} / \mathrm{H}_2, \mathrm{Cu}^{2+} / \mathrm{Cu}$. $\mathrm{Zn}^{2+} / \mathrm{Zn}$ and $\mathrm{NO}_3{ }^{-}, \mathrm{H}^{+} / \mathrm{NO}$ are $0.0,-0.34,-0.76$ and 0.97 V respectively. Observe the following reactions I. $\mathrm{Zn}+\mathrm{HCl} \rightarrow$ II. $\mathrm{Cu}+\mathrm{HCl} \rightarrow$ III. $\mathrm{Cu}+\mathrm{HNO}_3 \rightarrow$
Which reactions does not liberate $\mathrm{H}_2(\mathrm{~g})$ ?
  1. II, III only
  2. I, II only
  3. I, III only
  4. I. II, III

Solution

Higher the reduction potential less in the tendency to librate $\mathrm{H}_2$ gas.

Asked in: AP EAMCET 2024 (20 May Shift 2)

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