Which technique is not applicable for concentrating ${\mathrm{H}}_2{\mathrm{O}}_2$ solution?

$\mathrm{Y} \underset{{\mathrm{H}}_2/\mathrm{Pd}}{\overset{{\mathrm{O}}_2}{\rightleftarrows }} \mathrm{X}+{\mathrm{H}}_2{\mathrm{O}}_2$

In the above reaction, $\mathrm{X}$ and $\mathrm{Y}$, respectively are

Match the entry in Column 'I' with its corresponding entry in Column 'II'.

Hydrogen is prepared in the laboratory by treating granular zinc with dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$. Which of the following statements are true?

a. Dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$ does not react with pure zinc.
b. $\mathrm{KOH}$ solution removes the impurities of ${\mathrm{PH}}_3$ and ${\mathrm{AsH}}_3$ from the evolved ${\mathrm{H}}_2$.
c. With pure zinc and dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$, some ${\mathrm{CuSO}}_4$ has to be added.
d. Anhydrous ${\mathrm{CaCl}}_2$ is used to absorb moisture from evolved hydrogen.

Which statement is true about saline hydrides?
a. They are binary compounds of hydrogen and metallic elements.
b. They are crystalline solids.
c. They are generally volatile.
d. Their common examples are ${\mathrm{SiH}}_4, {\mathrm{CH}}_4$, etc.