The correct code for stability, of oxidation states for given cations is
 $\mathrm{I}. \mathrm{P}{\mathrm{b}}^{2+}>\mathrm{P}{\mathrm{b}}^{4+},\mathrm{T}{\mathrm{l}}^{+}<\mathrm{T}{\mathrm{l}}^{3+}$

$\mathrm{II}. \mathrm{B}{\mathrm{i}}^{3+}<\mathrm{S}{\mathrm{b}}^{3+},\mathrm{S}{\mathrm{n}}^{2+}<\mathrm{S}{\mathrm{n}}^{4+}$

$\mathrm{III}. \mathrm{P}{\mathrm{b}}^{2+}>\mathrm{P}{\mathrm{b}}^{4+},\mathrm{B}{\mathrm{i}}^{3+}>\mathrm{B}{\mathrm{i}}^{5+}$

$\mathrm{IV}. \mathrm{T}{\mathrm{l}}^{3+}<\mathrm{I}{\mathrm{n}}^{3+},\mathrm{S}{\mathrm{n}}^{2+}>\mathrm{S}{\mathrm{n}}^{4+}$

$\mathrm{V}. \mathrm{S}{\mathrm{n}}^{2+}<\mathrm{P}{\mathrm{b}}^{2+},\mathrm{S}{\mathrm{n}}^{4+}>\mathrm{P}{\mathrm{b}}^{4+}$

$\mathrm{VI}. \mathrm{S}{\mathrm{n}}^{2+}<\mathrm{P}{\mathrm{b}}^{2+},\mathrm{S}{\mathrm{n}}^{4+}<\mathrm{P}{\mathrm{b}}^{4+}$

Given below are two statements:

Statement I: During Electrolytic refining, the pure metal is made to act as anode and its impure metallic form is used as cathode.
Statement II: During the Hall-Heroult electrolysis process, purified ${\mathrm{Al}}_2{\mathrm{O}}_3$ is mixed with ${\mathrm{Na}}_3{\mathrm{AlF}}_6$ to lower the melting point of the mixture.
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 $\mathrm{A}$ and the other is labelled as Reason $\mathrm{R}$.

Assertion $\mathrm{A}:$ In $\mathrm{T}l{\mathrm{I}}_3,$ isomorphous to ${\mathrm{CsI}}_3$, the metal is present in $+1$ oxidation state.

Reason $\mathrm{R}:$ $\mathrm{T}l$ metal has fourteen $\mathrm{f}$ electrons in its electronic configuration.

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 $\mathrm{A}$ and the other is labelled as Reason $\mathrm{R}$

Assertion $\mathrm{A}$: Boron is unable to form ${\mathrm{BF}}_6^{3-}$

Reason $\mathrm{R}$: Size of $\mathrm{B}$ is very small.

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