Which one of the following statements is not correct about the reaction $H_2+C{l}_{2}2HCl?$

A$)HCl$ is the product.

B$)$ One molecule of hydrogen contains two atoms.

C$)$ Two molecules of $HCl$ are formed in the reaction.

D$)$ This reaction requires water.

E$)H_2$ and $C{l}_2$ are the reactants$/$substrates$.$