$(CH X_{3}) X_{2} N - CH X_{2} CH X_{2} - Cl$ is dissolved in water. The reactive intermediate that is formed by loss of chloride and that is then opened by water is

Aethylene oxide
Ba 2-(dimethylamino)ethyl carbocation, $(CH X_{3}) X_{2} N - CH X_{2} - CH X_{2} X^{+}$
C1,1-dimethylaziridine N-oxide
D1,1-dimethylaziridinium ion

Answer: D

The nitrogen lone pair displaces chloride intramolecularly (3-exo-tet) to give the strained cyclic 1,1-dimethylaziridinium ion. Water then opens the ring to give 2-(dimethylamino)ethanol. This is the nitrogen analogue of the episulfonium ion in sulfur mustard.

Practice Organic Reaction Mechanisms III: Nucleophilic Substitution More on Neighbouring group participation

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(CHX3​)X2​N−CHX2​CHX2​−Cl is dissolved in water. The reactive intermediate that is formed by loss of chloride and that is then opened by water is

Answer: D

More questions on Neighbouring group participation

$(CH X_{3}) X_{2} N - CH X_{2} CH X_{2} - Cl$ is dissolved in water. The reactive intermediate that is formed by loss of chloride and that is then opened by water is