1. (a) Is ammonia more dense or less dense than air? (b) What property of ammonia is demonstrated by the Fountain Experiment? (c) Write the balanced equation for the reaction between ammonia and sulphuric acid. 2. Pick the odd member from the list giving reasons: (a) Ammonia, sulphur dioxide, hydrogen chloride, carbon dioxide. (b) Copper oxide, aluminium oxide, sodium oxide, magnesium oxide. 3. Give reasons for the following : (a) Liquid ammonia is used as a refrigerant in ice plants. (b) Aqueous solution of ammonia is used for removing grease stains from woollen clothes. (c) Aqueous solution of ammonia gives a pungent smell. (d) Aqueous solution of ammonia conducts electricity.

(1) (a) ammonia is less dense than air

(b) solubility in water

(c) 2NH₃ + H₂SO₄ → (NH₄)₂SO₄

(2) (a) Ammonia → because - NH₃ is basic while, SO₂,HCl and CO₂ are acidic oxides.

(b) CuO, (copper oxide) because, it is less reactive and can be reduced by C,CO or H₂; while Al₂O₃, Na₂O and MgO are reduced only by electrolysis.

(3) (a) Liquid ammonia acts as a refrigerant in ice plants. it has high letent heat of vaporization. when liquid NH₃ vapourizes. it absorbs large quantities of Heat from sourronding without charging its temperature. because of that a liquid ammonia is widly used as a refrigerant.

(b) Ammonia emulsifies or dissolve fats,grease so it is used to remove grease from woolen clothes.

(c) Aqueous solution of ammonia gives pungent smell because of the ammonia gas.

(d) Aqueous solution of ammonia is a weak electrolyte. it dissociates partially to give hydroxyl ions and ions conduct electricity.