Question

Which of the following groups cannot participate in response with other suitable group:
A) $-COOH$
B) $-CO{O}^{-}$
C)$-COCl$
D)$-N{H}_3^{+}$
E)$-C{H}_2^{+}$

Answer 1

A) $-COOH$ can participate in resonance due to presence of $C=O$ bond. For example.

B) Like $-COOH$, ${COO}^{(-)}$ can participate in resonance. For example.

C) like $-COOH$, $COCl$ can participate in resonance, for example.

D) $-{NH}_3^{+}$ can't participate in resonance since it has no vacant orbital.

E) $-{\stackrel{(+)}{CH}}_2$ can participate in resonance because it has vacant $p-$ orbital. For example.

${CH}_2=CH-{\stackrel{(+)}{CH}}_2⟷{\stackrel{(+)}{CH}}_2-CH={CH}_2$

$\therefore$ Correct answer is D.