(a) Which one of the folJowing is a food preservative?
Equanil, Morphine, Sodium benzoate
(b) Why is bithional added to soap?
(c) Which class of drugs is used in sleeping pills?

Explanation

(a) Sodium benzoate is used as a food preservative whereas equanil is a tranquilizer and morphine is a narcotic analgesic.
(b) Bithional is an antiseptic so it is added to soaps to reduce odours producing bacterial decomposition of organic matter on the skin.
(c) Tranquilizers relieve stress, fatigue by inducing sense of well being, so they are used in the making of sleeping pills.