Haloalkanes and Haloarenes · Question 24

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below

1. Both Statement I and Statement II are correct
2. Statement I is incorrect but Statement II is correct
3. Both Statement I and Statement II are incorrect
4. Statement I is correct but Statement II is incorrect

Answer

(1) Both Statement I and Statement II are correct

Solution

In Et2N-CH2-CH2-Cl the lone pair on nitrogen attacks the carbon carrying Cl from the back side (intramolecular SN2, neighbouring group participation) and expels Cl-, giving a cyclic aziridinium ion:

Et2N-CH2CH2-Cl Et2 N(CH2)2 + Cl

Statement II is correct.

The strained three-membered aziridinium ion is opened very rapidly by OH-:

Et2 N(CH2)2 + OH- Et2N-CH2CH2-OH

In Et2CH-CH2CH2-Cl there is no such neighbouring group; it is an ordinary 1° alkyl chloride and is hydrolysed only by the slower direct SN2 attack of OH-.

The amino compound is hydrolysed faster Statement I is correct.

Answer: (1)