Question

Given below are two statements:
Statement I: The dipole moment of R–CN is greater than R–NC and R–NC can undergo hydrolysis under acidic medium to produce R–COOH.
Statement II: R–CN hydrolyses under acidic medium to produce a compound which on treatment with SOCl$_2$, followed by the addition of NH$_3$ gives another compound (X). This compound (X) on treatment with NaOCl/NaOH gives a product, that on treatment with CHCl$_3$/KOH/$\Delta$ produces R–NC.
In the light of the above statements, choose the correct answer from the options given below.

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Hint:

Nitriles hydrolyse to carboxylic acids, while isocyanides are formed from primary amines via the carbylamine reaction.

Answer 1

The Correct Option is D

Step 1: Evaluation of Statement I.
Although the dipole moment of R–CN is greater than that of R–NC, the statement incorrectly mentions that R–NC undergoes acidic hydrolysis to form R–COOH. In reality, nitriles (R–CN) undergo acidic hydrolysis to give carboxylic acids, whereas isocyanides (R–NC) do not. Hence, Statement I is false.
Step 2: Evaluation of Statement II.
R–CN undergoes acidic hydrolysis to form R–COOH. Treatment with SOCl$_2$ converts it into R–COCl, which on reaction with NH$_3$ forms R–CONH$_2$ (amide). The amide undergoes Hofmann degradation with NaOCl/NaOH to form R–NH$_2$, which on treatment with CHCl$_3$/KOH/$\Delta$ gives R–NC via the carbylamine reaction. Thus, Statement II is true.
Step 3: Conclusion.
Statement I is false and Statement II is true.