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 $\mathrm{H}_2(\mathrm{~g})$ ?

• Correct answer
  A

  II, III only
• B

  I, II only
• C

  I, III only
• D

  I. II, III

Hence, the correct answer is option: 'A'.