has lowest boiling point hence used in cryogenics (low temperature science). . It is much less denser than air and hence used for filling air balloons Neon: Neon is used in advertisement as neon sign and the brilliant red glow is caused by passing electric current through neon gas under low pressure. Argon: Argon prevents the oxidation of hot filament and prolongs the life in filament bulbs Krypton: Krypton is used in fluorescent bulbs, flash bulbs etc...
Lamps filed with krypton are used in airports as approaching lights as they can penetrate through dense fog. XII XII - - - - Xenon: Xenon is used in fluorescent bulbs, flash bulbs and lasers. Xenon emits an intense light in discharge tubes instantly. Due to this it is used in high speed electronic flash bulbs used by photographers Radon: Radon is radioactive and used as a source of gamma rays Radon gas is sealed as small capsules and implanted in the body to destroy malignant i.e.
cancer growth Summary Occurrence: About % of earth atmosphere contains dinitorgen (N ) gas. It is also present in earth crust as sodium nitrate (Chile saltpetre) and potassium nitrates (Indian saltpetre). Nitrogen , the principle gas of atmosphere ( % by volume) is separated industrially from liquid air by fractional distillation Ammonia is formed by the hydrolysis of urea. Nitric acid is prepared by heating equal amounts of potassium or sodium nitrate with concentrated sulphuric acid.
In most of the reactions, nitric acid acts as an oxidising agent. Hence the oxidation state changes from + to a lower one. It doesn’t yield hydrogen in its reaction with metals. The reactions of metals with nitric acid are explained in steps as follows: ▶ Primary reaction: Metal nitrate is formed with the release of nascent hydrogen ▶ Secondary reaction: Nascent hydrogen produces the reduction products of nitric acid.
▶ Tertiary reaction: The secondary products either decompose or react to give final products Phosphorus has several allotropic modification of which the three forms namely white, red and black phosphorus are most