$AlC{l_3}$ is

The structure of diborane contains :-

The purification of alumina is called

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. $H _{2} SO _{4}$ 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 $X, Y$ and $Z$

The formation of molecular complex $BF_3 – NH_3$ results in a change in hybridization of boron