(i) There are sodium salts of sulphonated long chain alcohols or hydrocarbons and large part of their molecules are anions e.g. sodium lauryl sulphate
(ii) If the antibiotics kill a single micro organism, then the antibiotics e.g. penicillin
(iii) Antiseptis : There are the chemicals which prevent either the mouth of micro organism or kill them but are not harmful to the living human tissues e.g. soframycin.