Question

Which of the following produces hydrolith with hydrogen?
(A) Mg
(B) Al
(C) Cu
(D) Ca

Answer 1

Hydrolith is a salt-like binary compound which has the name calcium hydride. It is an alkaline earth hydride. It is a source of hydrogen. The alkali metals and alkaline earth metals heavier than beryllium form all form alkaline earth hydride.

Complete answer:
We know that hydrolith is an alkaline earth hydride. Also the alkaline earth metals heavier than beryllium form alkaline earth hydride.
So here calcium reacts with dihydrogen to form hydrolith which is calcium hydride.
The concerned chemical reaction is as follows
$\rm{Calcium + Hydrogen \,gas \xrightarrow{\Delta} Calcium \,Hydride}$
Other metals being non-alkaline earth don't react with hydrogen to form hydrolith.
Therefore calcium reacts with hydrogen to form hydrolith.

**Hence the correct answer is option D

Additional Information:**
It is also called philosopher's stone and is used in immersion lithography.

Note:
Hydrolith is used as a source of hydrogen which is used for inflating air balloons. It is a saline hydride and doesn’t dissolve in solvents with which calcium hydride does not react.
Also, it reacts violently with water and therefore sometimes is used as a desiccant(to remove water or moisture).