Question

Knowing the properties of ${{\text{H}}_{\text{2}}}{\text{O}}$ and ${{\text{D}}_{\text{2}}}{\text{O}}$. Do you think ${{\text{D}}_{\text{2}}}{\text{O}}$ can be used for drinking purposes?

Answer 1

Hint: ${{\text{D}}_{\text{2}}}{\text{O}}$ is known as deuterium oxide or heavy water. The ${\text{D}}$ in ${{\text{D}}_{\text{2}}}{\text{O}}$ is known as deuterium. Deuterium is an isotope of hydrogen. The mass of deuterium is twice that of the mass of hydrogen.

Complete answer:
We know that the mass of deuterium is twice that of the mass of hydrogen. The molecular weight of heavy water is 20. Heavy water is tasteless, colourless and odourless. The dielectric constant of heavy water is lower than that of ordinary water and thus, ionic compounds are less soluble in heavy water.

Ordinary water is found from natural resources. Ordinary water contains one deuterium atom for every 6,760 hydrogen atoms. Deuterium oxide or heavy water is obtained by continued electrolysis of hundreds of litres of ordinary water until only a few millilitres of water remains.

Heavy water can also be prepared by fractional distillation. Heavy water is less volatile than ordinary water and thus, fractional distillation is an effective process for preparation of heavy water.
Heavy water is harmful to human beings. This is because heavy water slows down the rate of various reactions in the human body.Heavy water retards the processes like mitosis, cell division, etc. and thus, heavy water does not support life.

Use of heavy water for a longer time leads to degeneration of tissues in the body.Due to all these reasons heavy water or ${{\text{D}}_{\text{2}}}{\text{O}}$ cannot be used for drinking purposes.

Note: Heavy water is used as a moderator of neutrons in nuclear power plants. Pure heavy water kills small fishes, mice, etc. heavy water also retards the growth of living organisms like animals and plants.