List some important uses of bases.

1. Sodium hydroxide (caustic soda) is used in the manufacture of soap. It is used in petroleum-refining; in making medicines, paper, pulp, etc. It is used in making rayon.
2. Calcium hydroxide is also known as slaked lime. It is used to neutralize acid in water supplies; in the manufacture of bleaching powder; as a dressing material for acid burns; as an antidote for food poisoning; in the preparation of fungicides and in the mixture of whitewash. It is mixed with sand and water to make mortar which is used in the construction of buildings. It is also used by farmers on the fields to neutralize the harmful effects of acid rain.
3. Ammonium hydroxide is used to remove ink spots from clothes and to remove grease from window-panes. It is used in the cosmetic industry.
4. Alkalis are used in alkaline batteries. Generally, potassium hydroxide is used in such batteries.