IITJEE Chemistry Questions

1. A colorless solid A on heating gives a white solid B and a gas C; B gives off reddish brown fumes on treatment with dil acids. On heating with NH4Cl, B gives a colorless gas D and a residue E. The compd A also gives colorless gas F on heating with ammonium sulphate and white residue G. Both E and G impart yellow color to the Bunsen flame. C forms white powder with strongly heated Mg metal. The white powder forms Mg(OH)2 with H2O. The gas D on the other hand is observed by heated Ca which gives off ammonia on hydrolysis. Identify the substance A to G and give reactions for the changes involved.

2. A mix of 3 gases A, B, C is passed first into acidified dichromate solution when A is absorbed turning the soln green. The remainder ofthe gas is passed through excess of lime water which turns milky resulting in the absorption of B. The residual gas C is absorbed by alk pyrogallol soln. However the original mix does not turn lead acetate paper black.Identify A, B, C.