A certain salt (X) gives the following tests : (a) Its aqueous solution is alkaline to litmus. (b) On strong heating, it swells up to give a glassy material (Y). (c) When conc. H_(2) SO_(4) is added to a hot concentrated solution of (X), white crystal ofa weak acid (Z) separates out. Identify (X), (Y) and (Z) and write down the chemical equations for reaction at steps a, b and c.

A certain salt (X) gives the following tests : (a) Its aqueous soluti

1.	A certain salt (X) gives the following tests : (a) Its aqueous solution is alkaline to litmus. (b) On strong heating, it swells up to give a glassy material (Y). (c) When conc. H_(2) SO_(4) is added to a hot concentrated solution of (X), white crystal ofa weak acid (Z) separates out. Identify (X), (Y) and (Z) and write down the chemical equations for reaction at steps a, b and c.
Answer» Solution :(i) SINCE, the alkaline solution of the given salt [X] is alkaline to litmus, it MUST be a salt of strong base and weak acid. (ii) The salt [X] on heating SWELLS up to a GLASSY material (Y). Therefore, [X] should be borax and [Y] a mixture of sodium metaborate and boric anhydride. (iii) When conc. H2SO4 is added to a hot solution of borax [A], white crystals of orthoboric acid [Z] SEPARATE out. Hence, [X] = `Na_2 B_4 O_7 . 10 H_2 O , [Y] = NaBO_2 + B_2 O_3 and [Z] = H_3 BO_3`. The reaction can be expressed as follows :