Hydrogen And Its Compounds - Inorganic Chemistry - Chemistry Previous Year Questions

Observe the following reactions (not balanced)

$$\begin{aligned} & \mathrm{BF}_3+\mathrm{LiAlH}_4 \xrightarrow{\left(\mathrm{C}_2 \mathrm{H}_5\right)_2 \mathrm{O}} X+\mathrm{LiF}+\mathrm{AlF}_3{ }^{-} \\ & X+\mathrm{NaH} \longrightarrow Y \end{aligned}$$

The incorrect statement about $Y$ is

Oxidation state of hydrogen in compound $X$ is -1 and in compound $Y$ is $+1 . X$ and $Y$ are respectively

Temperature of maximum density of $\mathrm{H}_2 \mathrm{O}$ is $y \mathrm{~K}$ and $\mathrm{D}_2 \mathrm{O}$ is $x \mathrm{~K} .(x-y)($ in K$)$ is nearly