Pure nitric acid is a colourless liquid, but on exposure to light it turns brownish due to

Pure nitric acid is colorless liquid. But on exposure to light it turns brownish because nitric acid is decomposed photo-chemically and turns yellow. The reaction is given below- 3 2 2 2 ( ) O HNO NO H O l → Hence, the color arises due to slight decomposition of 3 HNO to 2 NO ,which is brown in color. Thus, the correct option is (b) 2 2 Ca [N C N] linear shape (sp-hybridised C-atom) On hydrolysis, calcium cyanamide gets converted into urea which then decomposes into ammonia. 2 2 CN is pseudohalide ion.