SODIUM PEROXIDE (NA2O2)

SODIUM PEROXIDE (Na2O2) Preparation : 1. By heating the metal in excess of air or oxygen at 300', which is free from moisture and CO2. 2Na + O2 (excess) --> Na2O2 2. Industrial method : It is a two stage reaction in the presence of excess air. 2Na + O2 --> Na2O Na2O + O2 --> Na2O2 Properties : 1. It is a pale yellow solid (when impure), becoming white in air from the formation of a film of NAOH AND NaCO3. 2. In cold water (~0'C) produces H2O2 but at room temperature produces O2. In ice cold mineral acids also produces H2O2. Na2O2 + 2H2O --> 2NaOH + H2O2 2Na2O2 + 2H2O --> 4NaOH + O2 Na2O2 + H2SO4 --> Na2SO4 + 2H2O +O2 3. It reacts with CO2, giving sodium carbonate and oxygen and hence its use for purifying air in a confined space e.g. Submarine, ill ventilated room. Na2O2 + CO --> Na2CO3 4. It is an oxidizing agent and oxidises charcoal, CO, NH3, SO2. 3Na2O2 + 2C --> 2Na2CO3 + 2Na [ deposition of metallic Na ] CO + Na2O2 --> Na2CO3 SO2 + Na2O2 --> Na2SO4 5. It contains peroxide ion [-O-O-]^-2 and it react with C6H5COCl formed benzoyl peroxide (BLEACHING agent ). So it acts as a powerful oxidising agent. a. Chromic compounds are oxidised to chromates. b. Manganous salt is oxidised to sodium mangamate. c. Sulphides are oxidised to corresponding sulphates