I, II and III

I and III only

II and III only

I and II only

Both $X$ and $Y$ are acidic in nature

$X$ is acidic and $Y$ is neutral in nature

Both $X$ and $Y$ are neutral in nature

$X$ is amphoteric and $Y$ is neutral in nature

Reaction of $\mathrm{BF}_3$ with $\mathrm{LiAlH}_4$ in diethyl ether

Oxidation of $\mathrm{NaBH}_4$ with $\mathrm{I}_2$

Reaction of $\mathrm{BF}_3$ with NaH at 450 K

By heating $\mathrm{H}_3 \mathrm{BO}_3$ to above 370 K temperature

Thermal stability: $\mathrm{H}_2 \mathrm{O}>\mathrm{H}_2 \mathrm{~S}>\mathrm{H}_2 \mathrm{Se}>\mathrm{H}_2 \mathrm{Te}>\mathrm{H}_2 \mathrm{PO}$

Reducing property: $\mathrm{H}_2 \mathrm{~S}>\mathrm{H}_2 \mathrm{Se}>\mathrm{H}_2 \mathrm{Te}>\mathrm{H}_2 \mathrm{Po}$

Boiling point : $\mathrm{H}_2 \mathrm{~S}<\mathrm{H}_2 \mathrm{Se}<\mathrm{H}_2 \mathrm{Te}<\mathrm{H}_2 \mathrm{O}$

Melting point : $\mathrm{H}_2 \mathrm{~S}<\mathrm{H}_2 \mathrm{Se}<\mathrm{H}_2 \mathrm{Te}<\mathrm{H}_2 \mathrm{O}$