Heavy water is prepared from the reaction of with oxygen.

Out of the oxides given below which of them cannot be reduced by ${\mathrm{H}}_2$?

$\mathrm{I}-{\mathrm{Al}}_2{\mathrm{O}}_3; \mathrm{II}-\mathrm{CuO}; \mathrm{III}-\mathrm{ZnO}$

Write the reaction involved when:

Nitrogen reacts with hydrogen.

How can hydrogen be made to combine with:

oxygen

Represent the union of two sets by Venn diagram for each of the following.

$X=\{x | x$ is a prime number between $80$ and $100\}$

$Y=\{y | y$ is an odd number between $90$ and $100\}$

How does hydrogen react with metals? Explain with the help of examples.

Complete the following reaction:
${\mathrm{H}}_2\left(\mathrm{g}\right)+{\mathrm{M}}_{\mathrm{m}}{\mathrm{O}}_{\mathrm{o}}\left(\mathrm{s}\right)\stackrel{∆}{\to }$