Q83 / 180 · AIIMS 2005 · Chemistry
Assertion : Alkyl isocyanides in acidified water give alkyl formamides.
Reason : In isocyanides, carbon first acts as a nucleophile and then as an electrophile.
- Correct answerAIf both assertion and reason are true and reason is the correct explanation of assertion
- BIf both assertion and reason are true but reason is not the correct explanation of assertion
- CIf assertion is true but reason is false
- DIf both assertion and reason are false.
Solution
In an isocyanide, first an electrophile and then a nucleophile add at the carbon to form a species which usually undergoes further transformations.
$$
\begin{array}{r}
R \stackrel{+}{\mathrm{N}} \equiv \overline{\mathrm{C}}+E^{+} \longrightarrow R \stackrel{+}{\mathrm{N}} \equiv \mathrm{CE} \stackrel{\mathrm{Nu}}{\longrightarrow} \mathrm{RN}=\mathrm{C}(\mathrm{Nu}) E \\
R_{+}^{\mathrm{N}} \equiv \overline{\mathrm{C}}+\mathrm{H}_2 \mathrm{O} \longrightarrow R \mathrm{~N}=\mathrm{CHOH} \longrightarrow R \mathrm{NHCHO}
\end{array}
$$
alkyl formamide
Hence, the correct answer is option: 'A'.