The gas used in the hydrogenation of oils in the presence of nickel as a catalyst is

Action of water or dilute mineral acids on metals can give

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

Identify the hydride which is not correctly matched with the example given in brackets?

What do you understand by $(i)$ electron deficient,$(ii)$ electron precise,and $(iii)$ electron rich compounds of hydrogen? Provide justification with suitable examples.

What do you expect the nature of hydrides is,if formed by elements of atomic numbers $15$,$19$,$23$,and $44$ with dihydrogen? Compare their behaviour towards water.