Chemistry - Hydrogen and Its compound Question with Solution | TestHub

Deuterium oxide ($D_{2}O$), or heavy water, has a molar mass of $2\times 2.014+16.00=20.028$ g/mol, which is greater than that of ordinary water ($H_{2}O$, $18.015$ g/mol). Therefore, 100 mL of $D_{2}O$ weighs more than 100 g (since its density is $\approx 1.105$ g/mL at 25 °C). $D_{2}O$ is used as a moderator in nuclear reactors to slow down neutrons. Its boiling point is $374.42$ K ($101.27$ °C), not $373$ K. It is also used in exchange reactions to study reaction mechanisms.

Final Answer: The final answer is $\boxed{A,B,D}$