Q.1. If metal ions of group III are precipitated by NH4Cl and NH4OH without prior oxidation by conc. HNO3 ............. is not completely precipitated. (1984 - 1 Mark)
Sol. Fe3+; Without oxidation with HNO3, the Fe2+ ions present would not be converted into Fe3+. So Fe(OH)2 will not be precipitated as its solubility product is higher than that of Fe(OH)3 and as NH4Cl suppresses the ionisation of NH4OH, this solubility product is not reached.
Q.2. The formula of the deep red liquid formed on warming dichromate with KCl in concentrated sulphuric acid is ............. . (1993 - 1 Mark)
Sol. Chromyl chloride (CrO2Cl2).