A certain salt X gives the following results:
(i) Its aqueous solution is alkaline to litmus.
(ii) It swells up to a galssy material Y on strong heating.
(iii) When conc. `H_(2)SO_(4)` is added to a hot solution of X, white crstals of an acid Z separate out.
Write equations for all the above reactions and identify x,y and Z.

Explanation

(i) Since the aqueous solution of salt (X) is alkaline to litmus, it must be the salt of a strong base and a weak acid.
(ii) Since the salt (X) swells up to a glassy material (Y) on strong heating, therefore (X) must be borax and (Y) must be a mixture of sodium metaborate and boric anhydride.
(iii) When conc. `H_(2)SO_(4)` is added to a hot solution of X, i.e, borax, white crystals of an acid (Z) separate out, therefore (Z) must be orthobasic acid. The equations for the reactions involved in the question are :
(i) `underset("Borax (X)")(Na_(2)B_(4)O_(7). 10 H_(2)O) overset("Water")rarr underset(("Strong alkali"))(2NaOH)+ underset(("Weask acid"))(H_(2)B_(4)O_(7) + 8H_(2)O`
(ii) `underset((X))(Na_(2)B_(4)O_(7).10H_(2)O)overset("Heat")rarrNa_(2)B_(4)O_(7)+10H_(2)O, Na_(2)B_(4)O_(7) overset("Heat")rarrubrace(2NaBO_(2) + B_(2)O_(3))_("Glassy material")`
(iii) `Na_(2)B_(4)O_(7).10H_(2)O+H_(2)SO_(4)rarrunderset(" Boric acid (Z) ")(4H_(3)BO_(3))+Na_(2)SO_(4)+5H_(2)O`