Allotropy is the existence of an element in more than one form, having the same chemical properties but different physical properties. The various forms of an element are called allotropes. For example, carbon exists in three allotropic forms: diamond, graphite, and fullerenes.
The atoms of some elements (such as carbon) can link with one another through strong covalent bonds to form long chains or branches. This property is known as catenation. It is most common in carbon and quite significant in Si and S.
Q: 30. A certain salt X, gives the following results.
(i) Its aqueous solution is alkaline to litmus
(ii) It swells up to a glassy material Y on strong heating
(iii) When conc. is added to a hot solution of X, white crystal of an acid Z separates out.
Write equations for all the above reactions and identify and .
The given salt is alkaline to litmus. Therefore, X is a salt of a strong base and a weak acid. Also, when X is strongly heated, it swells to form substance Y. Therefore, X must be borax.
When borax is heated, it loses water and swells to form sodium metaborate. When heating is continued, it solidifies to form a glassy material Y. Hence, Y must be a mixture of sodium metaborate and boric anhydride.
When concentrated acid is added to borax, white crystals of orthoboric acid are formed.
Q: 31. Write balanced equations for: