Identify chiral and achiral molecules in each of the following pairs of compounds.

Explanation

In structure (1), the second carbon atom from left is attached to four groups `(-OH, -H, CH_3, CH_2 CH_3)`. Hence, it is a chiral molecule. In structure (ii) the central carbon atom has two identical `-CH_2CH_3` groups neither side of the central carbon atom. Therefore, structure (ii) is achiral.