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

According to availbale information
Compound (X) `overset(LiAIH)rarr"Hydride"(Y)` (contains 21.72% hydrogen)+other produce
Hydride (Y) `overset(O_(2)("air"))rarrB_(2)O_(3)`+other products.
The data shows that the compound (X) is a boron compound an composed (Y) is a hydride of boron which reacts explosively with air to form `B_(2)O_(3)` . The boron (Y) is most probably diborane `(B_(2)H_(6))` because it contains in it nearly 21.72% hydrogen which can be calculated as follows:
`B_(2)H_(6)-=6H`
`(2xx10.8xx6xx1)` parts ( 6xx1) parts
27.6g 6.0g
% of hydrogen (H) in `B_(2)H_(6)=((6.0 g))/((27.6g))xx100=21.74%`
Thus, the compound (X) is a halde of boron (e.g. `BF_(3)` or `BCl_(3)`) and the reaction involved is: ltbr. `4BCl_(3)+3LiAIH_(4)rarr3AICl_(3)+3LiCl+2B_(2)H_(6)` ltbr. [X] [Y]
`B_(2)H_(6)+3O_(2)overset("Heat")rarrB_(2)O_(3)+3H_(2)O`
For the structure of diborane, please consult section 11.4.