During the electrolysis of fused calcium hydride $(CaH_2)$,where is hydrogen produced?

The total number of isotopes of hydrogen and the number of radioactive isotopes among them,respectively,are:

Identify the catalyst $(A)$ used in the following reaction:
$CO + H_2O \rightleftharpoons CO_2 + H_2$

How can $D_2O$ be prepared from water? Mention the physical properties in which $D_2O$ differs from $H_2O$. Give at least three reactions of $D_2O$ showing the exchange of hydrogen with deuterium.

Which of the following pairs will not produce dihydrogen gas?

Match List-$I$ with List-$II$.

List-$I$ (Hydrides)	List-$II$ (Nature)
$a. MgH_2$	$i. \text{Electron precise}$
$b. GeH_4$	$ii. \text{Electron deficient}$
$c. B_2H_6$	$iii. \text{Electron rich}$
$d. HF$	$iv. \text{Ionic}$

Choose the correct answer from the options given below: