A colourless solid (A) on hydrolysis produces a heavy white ppt. (B). Solid (A) gives a clear solution in conc. HCl; however, when added to large amount of water, it again gives ppt. (B). When H2 S is passed through a suspensions of (A) or (B), a brown black ppt. of (C) is obtained. Compound (A) liberates a gas (D) on treating with H2 SO4. The gas (D) is water soluble and gives white ppt. (E) with solution of mecurous salt but not with mercuric salt. Identify (A) to (E). Also report (A), (B), (C) if (C) is orange ppt..
