Q.a) Chemotherapy is a term found in medical terminology. What is chemotherapy?

Chemotherapy is the use of chemicals to treat disease; synthetic detergents fall into anionic, cationic, and non-ionic categories, and liquid dish-washing detergents belong to the non-ionic category.

a) Chemotherapy

Chemotherapy is the branch/approach of using specific CHEMICAL substances (drugs) to treat or cure a disease — the drug acts on the disease-causing organism, or on abnormal (e.g. cancerous) cells, while causing minimal or no harm to the normal cells/tissues of the host (target-specificity, based on differences in biochemistry between host and pathogen/abnormal cell).

b) i) Three categories of synthetic detergents

1. Anionic detergents — the detergent (surface-active) part of the molecule carries a negative charge, e.g. sodium salts of alkylbenzene sulphonates.
2. Cationic detergents — the surface-active part carries a positive charge, usually quaternary ammonium salts, e.g. cetyltrimethylammonium bromide.
3. Non-ionic detergents — the molecule carries no ionic charge at all, e.g. formed by the reaction of a polyethylene glycol with a fatty (stearic) acid. …