Question

why boron does not react with hydrogen directly?

Answer 1

Hydrogen and the p-Block Elements. Covalent hydrides are formed when hydrogen reacts with the p-block nonmetals by sharing its electrons. ... Relative to hydrogen's reaction with other elements, hydrogen can readily react with nitrogen, oxygen, and halogens because they are very electronegative, therefore reactive.

Answer 2

Boron is an inert element and does not react directly either with water or air. It reacts to some extent with air when heated. But boron remains inert with water even with hot water.Action of acids: Boron reacts only with nitric acid forming boric acid.