Question

Heavy water ($D_{2}O$) is

• A. a product of oxygen and hydrogen
• B. water of mineral springs
• C. water obtained by repeated distillation and condensation
• D. ordinary water containing dissolved salts of heavy metals

Answer 1

The correct option is C

water obtained by repeated distillation and condensation

Heavy water is the molecule of water which has the second isotope of hydrogen i.e., "deuterium" rather than an H atom. Hence heavy water has a slightly higher boiling point than $H_{2}O$.
The difference in mass can be utilised to separate heavy water from regular water by repeated distillation.