HNO + (H) NH + Hydroxylamine Ammonia 3H O 2HNO + (H) H N O + 4H O Hypo nitrous acid XII XII - - - - Tertiary reaction: The secondary products either decompose or react to give final products Decomposition of the secondary: HNO HNO + NO Nitrous acid Nitric acid Nitric oxide + H O HNO N O + H Nitrous acid Dinitrogentrioxide H N O N O + H O Hypo nitrous acid Nitrous oxide Reaction of secondary products: HNO NH N + 2H O HNO NH OH N O + 2H O HNO HNO 2NO + H O Examples: Copper reacts with nitric acid in the following manner 3Cu + 6HNO 3Cu(NO ) + (H) (H) + 3HNO 3HNO + H O 3HNO HNO + 2NO + H O overall reation 3Cu + 8HNO 3Cu(NO ) + 2NO + 4H O The concentrated acid has a tendency to form nitrogen dioxide Cu + 4HNO Cu(NO ) + 2NO + 2H O Magnesium reacts with nitric acid in the following way 4Mg + 8HNO 4Mg(NO ) + [H] HNO + (H) NH + 3H O HN O + NH NH NO overall reaction 4Mg + 10HNO 4Mg(N O ) + NH NO + 3H O If the acid is diluted we get N O 4Mg + 10HNO 4Mg(NO ) + N O + 5H O Uses of nitric acid: . Nitric acid is used as a oxidising agent and in the preparation of aquaregia. . Salts of nitric acid are used in photography (AgNO ) and gunpowder for firearms.
(NaNO ) Evaluate yourself : Write the products formed in the reaction of nitric acid (both dilute and concentrated) with zinc. XII XII - - - - . . Oxides and oxoacids of nitrogen Name Formula Oxidation state Physical properties Preparation Nitrous oxide N O + Colourless gas & neutral NH NO →N O +