Ncert Exercises & Solutions

Which of the following compounds will give racemic mixture on nucleophilic substitution by OH $^{-}$ ion?

1. (iii)
2. (i), (ii) and (iii)
3. (ii) and (iii)
4. (i) and (iii)

A mixture containing two enantiomers in equalimolar amount have zero optical

rotation, as the rotation due to one isomer is cancelled by the rotation due to other

isomer. Such a mixture is known as racemic mixture. All those compounds which

follow s $_{N}$ 2 mechanism during nucleophilic substitution reaction form racernic mixture.

Order of reactivity of alkyl halides.towards S $_{N}$ 1.

and reactions as follows:

Tertiary halide; secondary halide; primary hatide; CH $_{3}$ X.

For S $_{N}$ 1 reaction.

Thus, $C H_{2} — C H — B r$
$|$
$C_{2} H_{5}$ contains a chiral carbon and gives a racemic product.

Hence, option (a) is correct.