Which of the following statements regarding heavy water are correct?

1. It is extensively used as a moderator in nuclear reactors
2. It cannot be used in exchange reaction to study reaction mechanism
3. Viscosity of heavy water is relatively smaller than that of ordinary water
4. The dielectric constant of heavy water is smaller than that of ordinary water

Select the correct answer using the code given below:

1 and 2

2 and 3

3 and 4

1 and 4

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-2 – 2015

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Statement 1 is correct: Heavy water (D₂O) is an excellent moderator in nuclear reactors because deuterium has a low neutron absorption cross-section and can effectively slow down fast neutrons to thermal energies. Statement 2 is incorrect: Heavy water and deuterated compounds are commonly used in isotopic exchange reactions to study reaction mechanisms and kinetics. Statement 3 is incorrect: The viscosity of heavy water is slightly higher than that of ordinary water at typical temperatures. Statement 4 is correct: The dielectric constant of heavy water is slightly smaller than that of ordinary water.

This question tests specific properties of heavy water compared to ordinary water.

Heavy water is chemically similar to ordinary water but has different physical properties due to the heavier deuterium isotope replacing hydrogen. It is essential for some types of nuclear reactors (like CANDU reactors) that use unenriched uranium fuel.

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