Given below are two statements :

Statement I : The number of pairs, from the following, in which both the ions are coloured in aqueous solution is 3.

$$ \left[\mathrm{Sc}^{3+}, \mathrm{Ti}^{3+}\right],\left[\mathrm{Mn}^{2+}, \mathrm{Cr}^{2+}\right],\left[\mathrm{Cu}^{2+}, \mathrm{Zn}^{2+}\right] \text { and }\left[\mathrm{Ni}^{2+}, \mathrm{Ti}^{4+}\right] $$

Statement II : $\mathrm{Th}^{4+}$ is the strongest reducing agent among $\mathrm{Th}^{4+}, \mathrm{Ce}^{4+}, \mathrm{Gd}^{3+}$ and $\mathrm{Eu}^{2+}$.

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

$20.0 \mathrm{dm}^3$ of an ideal gas ' X ' at 600 K and 0.5 MPa undergoes isothermal reversible expansion until pressure of the gas is 0.2 MPa . Which of the following option is correct?

(Given: $\log 2=0.3010$ and $\log 5=0.6989$ )

In period 4 of the periodic table, the elements with highest and lowest atomic radii are respectively.

Method used for separation of mixture of products ( B and C ) obtained in the following reaction is