Laughing gas is obtained by heating of………….

Calculate the weight of lime (CaO) obtained by heating 200 kg of 95% pure lime stone (CaCO_3) .

When a cupric salt is heated with metallic copper and conc. HCl, a colourless solution is obtained because of the formation of

The major product obtained on heating phenol with a, solution of mixture of KBr and KBrO_3 is.

When a white crystalline compound 'X' is heated with K_(2)Cr_(2)O_(7) and concentrated H_(2)SO_(4) a red dish brown gas 'A' is evolved. On passing 'A' into caustic soda solution, a yellow coloured solution of 'B' is obtained. Neutralising the solution 'B' with acetic acid and on subsequent addition of lead acetate a yellow precipitate C is obtained. When 'X' is heated with NaOH a colourless gas is evolved and on passing this a gas into K_(2)HgI_(4) (Nessler's reagent) solution a reddish brown precipitate D is formed. Identify '(A), (B), (C), (D) and X. Write equations for the reactions involved.