Which of the following metals is capable of occluding hydrogen?

Which of the following combinations represents water gas?

What is obtained by the reaction of $HCOOH$ with concentrated $H_2SO_4$?

If an isotope of hydrogen has two neutrons in its atom,its atomic number and atomic mass number will respectively be

Very pure hydrogen $(99.9 \%)$ can be made by which of the following processes?

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Loss of electron from hydrogen atom results in a nucleus of $\sim 1.5 \times 10^{-3} \ pm$ size.
Reason $(R)$: Proton $(H^+)$ always exists in combined form.
In the light of the above statements,choose the most appropriate answer from the options given below: