During the borax bead test with ${\mathrm{CuSO}}_4$, a blue green colour of the bead was observed in oxidising flame due to the formation of

Given below are two statements:

Statement I: The decrease in first ionization enthalpy from $\mathrm{B}$ to $\mathrm{Al}$ is much larger than that from $\mathrm{Al}$ to $\mathrm{Ga}$.

Statement II: The d orbitals in $\mathrm{Ga}$ are completely filled.

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

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

Assertion (A): In expensive scientific instruments, silica gel is kept in watch-glasses or in semipermeable membrane bags.

Reason (R): Silica gel adsorbs moisture from air via adsorption, thus protects the instrument from water corrosion (rusting) and / or prevents malfunctioning.

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

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.