Which of the following reagents converts both acetaldehyde and acetone to alkanes ?

• A

  $\mathrm{Ni} / \mathrm{H}_2$
• B

  $\mathrm{LiAlH}_4$
• C

  $\mathrm{I}_2 / \mathrm{NaOH}$
• Correct answer
  D

  $\mathrm{Zn}-\mathrm{Hg} /$ conc. HCl

Solution

Clemmensen's reduction (conc. $\mathrm{HCl} / \mathrm{Zn}-\mathrm{Hg}$ ) or Wolf-Kishner reduction $\left(\mathrm{C}_2 \mathrm{H}_5 \mathrm{ONa} / \mathrm{NH}_2 \mathrm{NH}_2\right)$ can be used to convert $\gt\mathrm{C}=\mathrm{O}$ group into $\gt\mathrm{CH}_2$ group.

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