Question

The percentage weight of deuterium in heavy water is:
A. 80%
B. 60%
C. 40%
D. 20%

Answer 1

Deuterium, ($D$ or $^{2}H_1$), also called heavy hydrogen, isotope of hydrogen along with a nucleus consisting of one proton and one neutron, which is double the mass of the nucleus of ordinary hydrogen (one proton). Deuterium has an atomic weight of 2.014.

Complete step by step solution:
Deuterium goes into all substance responses normal for standard hydrogen, shaping comparable mixes. Deuterium, in any case, responds more gradually than customary hydrogen, a model that recognizes the two types of hydrogen. Due to this property, among others, deuterium is broadly utilized as an isotopic tracer in examinations of compound and biochemical responses including hydrogen.
Heavy water (${{D}_{2}}O$) is also called deuterium oxide.
Deuterium, the hydrogen isotope, has a mass double that of ordinary hydrogen.
The molecular weight of ${{D}_{2}}O=2(2)+16=20g/mol$
The percentage weight of deuterium in heavy water is $4/20*100=20 \%$

**Hence, the correct option is D. $20 \%$

Additional information: **
At the point when water is electrolyzed—i.e., deteriorated by an electric ebb and flow (really a water arrangement of an electrolyte, as a rule sodium hydroxide, is utilized)the hydrogen gas created contains a littler part of deuterium than the rest of the water, and, consequently, deuterium is packed in the water. Practically unadulterated deuterium oxide (${{D}_{2}}O$; substantial water) is made sure about when the measure of water has been decreased to around 100 thousandth of its unique volume by proceeded with electrolysis.

Note:
The atomic combination of deuterium iotas or of deuterium and the heavier hydrogen isotope, tritium, at high temperature is joined by arrival of a huge measure of energy; such responses have been utilized in nuclear weapons. Since 1953, the steady strong substance lithium deuteride ($LiD$) has been utilized instead of both deuterium and tritium.