1An unknown rock X was discovered in Ukraine Test with dilute sulphuric VIacid shows rapid effervescence with production of a colourless gas A that forms a white precipitate with lime water and colourless solution B On adding 3cm3 of 2M sodium hydroxide a white precipitate C is formed that dissolves to form a colourless solution D on adding more sodium hydroxide On adding 2M aqueous ammonia a white precipitate E is formed which persist in excess aqueous ammoniaOn which on adding 5cm3 of 1M LeadIInitrateV to F a white precipitate G is formed which remains on heating