The name hydrogen was given by

Dihydrogen can be prepared by which of the following reactions?
$(I)$ Reaction of granulated $Zn$ with dil. $HCl$
$(II)$ Reaction of $Zn$ with aq. $NaOH$
$(III)$ By heating calcium hydrogen carbonate

Which statement is not correct for ortho and para hydrogen?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Physical properties of isotopes of hydrogen are different.
Reason $R$: Mass difference between isotopes of hydrogen is very large.
In the light of the above statements,choose the correct answer from the options given below:

Calcium imide on hydrolysis will give gas $(B)$ which on oxidation by bleaching powder gives gas $(C)$. Gas $(C)$ on reaction with magnesium gives compound $(D)$. $(D)$ on hydrolysis gives again gas $(B)$. $(B)$,$(C)$ and $(D)$ are

Which of the following is not an isotope of hydrogen?