Question

How \[{{D}_{2}}O\]can be obtained ?
A. Repeated distillation
B. Exchange process
C. Neutron emitting radioactive decay in presence of water
D. Exhaustive electrolysis of alkaline water

Answer 1

Hint: \[{{D}_{2}}O\]is known as the heavy water which is referred as the water which is composed of deuterium. The other name for heavy water is deuterium oxide. Deuterium is the isotope of hydrogen whose mass is double that of ordinary hydrogen. The molecular weight of the deuterium oxide or heavy water is 20\[gmo{{l}^{-1}}\].

Complete step-by-step answer: The formation or production of heavy water can be by the prolonged electrolysis. Firstly when the ordinary water is electrolysed the formation of protium takes place. The protium is liberated readily in the case of water because the hydrogen ions tend to have more mobility in comparison to the \[{{D}^{+}}\]ions. They also tend to possess low discharge potential and due to which the hydrogen ions are discharged at the cathode easily. In addition to this the atoms of hydrogen form the molecular hydrogen more readily than the deuterium atoms. The increase in the concentration of heavy water is seen on the continuation of electrolysis. We can get almost pure heavy water when little volume is remaining. Urey, Brown and Degget designed the electrolytic cell for preparing the heavy water. It is a cathode. The use of a large number of these cells is done for the electrolysis of water.
The heavy water can be produced by fractional distillation also or the repeated distillation. The difference between the boiling points of the heavy and normal water is small. This is the basis of using the method of fractional distillation for preparing heavy water. We can also produce the heavy water by exchange process or chemical exchange process. It depends on the displacement of the isotopes at the equilibrium in the certain reactions which results in the concentration of the deuterium in one component.
So the correct answer is option A, B and D which are repeated distillation, exchange process and the exhaustive electrolysis of the alkaline water.

Note: The heavy water is colourless and odourless but it is heavy then the normal water. The ionic compounds are less soluble in heavy water as its dielectric constant is less than water. The tobacco seeds do not grow in heavy water. The pure heavy water tends to kill tadpoles and small fishes.