Chemistry
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.
Answer
(a) Liquid ammonia is a clear, colourless liquid under pressure. It evaporates rapidly and produces cooling effect. Moreover, Ammonia is environmentally compatible, has superior thermodynamic properties and its leaks are easily detectable due to its recognizable odour. All these reasons make liquid ammonia a good refrigerant.
(b) As aqueous solution of ammonia emulsifies or dissolves fats, grease etc., hence it is used for removing grease stains from woollen clothes.
(c) Pungent smell of aqueous solution of ammonia is due to the presence of ammonia, which has strong, pungent choking smell.
(d) In aqueous solution, the ammonia molecule combines with a hydrogen atom H+ by sharing the lone pair of electrons of nitrogen atom to form ammonium ion (NH4+). Thus, in water, ammonium hydroxide (NH4OH) dissociates into NH4+ (ammonium ion) and OH- (hydroxide ion) as follows:
NH4OH ⟶ NH4+ + OH-
Due to this ionisation, aqueous solution of ammonia (NH4OH) conducts electricity.
Related Questions
Ammonia solution in water gives a blue precipitate when it combines with a solution of copper salt. The blue precipitate further dissolves in excess of ammonia solution to give an azure blue solution. Explain with equation.
(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.
A gas 'P' gives dense white fumes with chlorine. It's aqueous solution gives a blue colour with copper (II) hydroxide. Give the name and formula of the gas P.
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.