Boric acid in solid, whereas ${\mathrm{BF}}_3$ is gas at room temperature because of

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Amongst $\mathrm{He}, \mathrm{Ne}, \mathrm{Ar}$ and $\mathrm{Kr}$; $1 \mathrm{g}$ of activated charcoal adsorbs more of $\mathrm{Kr}$.

Reason R: The critical volume ${\mathrm{V}}_{\mathrm{c}} ({\mathrm{cm}}^3 {\mathrm{mol}}^{–1})$ and critical pressure ${\mathrm{P}}_{\mathrm{c}}$ (atm) is highest for Krypton but the compressibility factor at critical point ${\mathrm{Z}}_{\mathrm{c}}$ is lowest for Krypton.

In the light of the above statements, choose the correct answer from the options given below.

Given below are two statements:

Statement I: Chlorine can easily combine with oxygen to from oxides: and the product has a tendency to explode.

Statement II: Chemical reactivity of an element can be determined by its reaction with oxygen and halogens.

In the light of the above statements, choose the correct answer from the options given below