What is $X$ in the following reaction?
$CO + 2 H_2 \xrightarrow{X} CH_3 OH$

Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.

The sum of the number of protons and neutrons in all isotopes of hydrogen is .......

Which of the following statements are $NOT$ correct?
$A$. Hydrogen is used to reduce heavy metal oxides to metals.
$B$. Heavy water is used to study reaction mechanism.
$C$. Hydrogen is used to make saturated fats from oils.
$D$. The $H-H$ bond dissociation enthalpy is lowest as compared to a single bond between two atoms of any elements.
$E$. Hydrogen reduces oxides of metals that are more active than iron.
Choose the most appropriate answer from the options given below:

Atoms in hydrogen gas have a preponderance of which isotope?

Given below are two statements:
Assertion $(A)$: Protium and deuterium differ in their rates of reactions.
Reason $(R)$: They have different enthalpies of bond dissociation.
The correct answer is: