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)`.