Question

The molecular formula of heavy water is:
A. ${D_3}O$
B. ${D_2}O$
C. $DO$
D. $D{O_2}$

Answer 1

According to this question, firstly we should know the composition of heavy water. And then check why this form of water is known as heavy water. And also why plain water is different from the heavy water.

Complete step by step solution:
The molecular formula of heavy water is ${D_2}O$. Heavy Water is composed of deuterium instead of hydrogen, whereas regular hydrogen has one proton in its nucleus, the deuterium has both one proton and one neutron. And this additional neutron makes a deuterium atom roughly twice as heavy as a protium atom. And plain water has two hydrogen and one oxygen atom. Thus, due to deuterium, it becomes heavier.
In plain water, each hydrogen atom contains a single proton in its nucleus. But in heavy water, each hydrogen atom is indeed heavier, with a neutron and a proton in its nucleus. This isotope of hydrogen is known as deuterium, and the presence of this heavy hydrogen isotope gives the water different nuclear properties and the increase of mass gives it slight changes in its physical and chemical properties when compared to normal water. When heavy water is in its pure form, then it has a density of 11% more than the normal water.

Hence, the correct option is (B).

Note: Heavy water is not entirely safe as drinking water because it is not radioactive, and deuterium in a heavy water forms stronger hydrogen bonds than protium, resulting in a different reactivity. If we drink heavy water, then our blood pressure starts reducing.