Which one of the following is the most abundant element in the universe?

In the reaction:
$2x + B_2H_6 \longrightarrow [BH_2(x)_2]^+ [BH_4]^-$
the amine $x$ will not be:

What is Carbogen?

Hydrogen generally forms covalent compounds. Give reason.

Which of the following explanations is best for not placing hydrogen in either the group of alkali metals or halogens?

Carbongene has $X\%$ of $CO_2$ and is used as an antidote for poisoning of $Y.$ Then,$X$ and $Y$ are