Compound `(X)` on reduction with `LiAlH_(4)` gives a hydride `(Y)` containing `21.72 %` hydrogen along with other products. The compound `(Y)` reacts with air explosively resulting in formation of boron trioxide. Identify `(X)` and `(Y)`.
Give balanced reactions involved in the formation of `(Y)` and its reaction with air. Give the structure of `(Y)`.

Explanation

Compound `X` on reduction with `LiAlH_(4)` gives a hydride `Y` containing `21.72 %` hydrogen along with other products. Compound `Y` reacts with air explosively, resulting in boron trioxide. `Y` seems to be a hydride of boron, may be `B_(2)H_(6)`. Molecular mass of hydride :
Percentage of `H` in `B_(2)H_(6) = (Mass of H)/(Mass of B_(2) H_(6)) xx 100`
=`(6)/(27.6) xx 100 = 21.73 %`
This matches the given data, so the hydride is `B_(2)H_(6)`.
`X` is some halide of boron which is reduced to `B_(2)H_(6)` with lithium aluminium hydride.
`4BX_(3)+3LiAlH_(4)to 2B_(2)H_(6) +3AlX_(3)+ 3LiX`
`B_(2)H_(6)+3O_(2) to B_(2)O_(3) + 3H_(2)O`.