(a) Acids are those chemical substances that have a sour taste. Example: Acetic acid and citric acid. Base is a chemical substance that has a bitter taste. Example: Caustic soda and washing soda.(b) Strong bases – Sodium hydroxide (NaOH), potassium hydroxide (KOH). Weak bases – Calcium hydroxide \\\\((Ca(OH_2))\\\\), ammonium hydroxide \\\\((NH_4OH)\\\\). (c) (i) When an acid is dissolved in water Hydrogen ions are found.(ii) When a base (or alkali) is dissolved in wate Hydroxide ions are found.(d) Neutralisation reaction between acids and bases: \\\\(\\underset{Hydrogen\\ ions \\ (From \\ acid)}{H^+ (aq)}+ \\underset{Hydroxide\\ ions \\ (from \\ bases)}{OH^- (aq)} \\xrightarrow[Reaction]{Neutralisation} \\underset{Water}{H_2O(l)}\\\\)(e) Two important uses of bases are: (i) Sodium hydroxide is used in the manufacture of soap, paper and rayon. (ii) Calcium hydroxide is used in the manufacture of bleaching powder.