Identify the correct statements about boron.

I. It has high melting point.

II. It has high density.

III. It has high electrical conductivity.

IV. B-10 isotope of it has high ability to absorb neutrons.

Assertion (A) HCl gas is dried by passing through concentrated H$$_2$$SO$$_4$$.

Reason (R) HCl gas reacts with NH$$_3$$ that gives white fumes.

What would be the product of following reaction?

$$\mathrm{SiCl}_4 \stackrel{\text { Excess of } \mathrm{H}_2 \mathrm{O}}{\longrightarrow} \text { ? (Major product) }$$

Identify (P) and (Q) in the following reaction.