Explain the following types of substances with one suitable example , for each case :
(i) Cationic detergents .
(ii) Food preservatives .
(iii) Analgesics.

Explanation

(i) Cationic detergents : Which are mostly acetates or chlorides of quaternary amines e.g., Cetyltrimethyl ammonium chloride.
(ii) Food preservatives : These are the substances used to prevent spoilage of food due to microbial growth during storage . The most common preservations used are sodium benzoate , sodium metabisulphite , etc . Salt-sugar and oils also act as food preservatives and have been used for many years.
(iii) Analgesics : The medicines which are used to relieve body pain are known as analgesics e.g., Novalgin , butazolidine , etc.