Benzaldehyde can be converted to benzonitrile by treatment with

• A

  $\mathrm{NH}_3$
• B

  $\mathrm{NH}_3$ followed by reaction with $\mathrm{C}_6 \mathrm{H}_5 \mathrm{SO}_2 \mathrm{Cl}$
• Correct answer
  C

  $\mathrm{NH}_2 \mathrm{OH}$ followed by reaction with acetic anhydride
• D

  $\mathrm{NH}_2 \mathrm{OH}$

Solution

When benzaldehyde reacts with $\mathrm{NH}_2 \mathrm{OH}$ (hydroxyl amine) then oxime is formed. Further oxime gives benzonitrile on heating.
$$ \text { Thus, option (3) is correct. } $$

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