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Heavy water
Concepts tested here
- Properties of heavy water
All Questions
2010 AIPMT-MAINS 1 question
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Some statements about heavy water are given below
a. Heavy water is used as a moderator in nuclear reactors
b. Heavy water is more associated than ordinary water
c. Heavy water is more effective solvent than ordinary water
Which of the above statements are correct?(a) is correct: heavy water ($D_2O$) slows down fast neutrons without absorbing them appreciably, so it is used as a moderator in nuclear reactors.
(b) is correct: $D_2O$ has stronger intermolecular (deuterium) bonding than $H_2O$, so it is more associated; this shows in its higher boiling point (374.4 K against 373 K), higher melting point (276.8 K) and higher enthalpy of vaporisation.
(c) is wrong: the dielectric constant of $D_2O$ (78.06) is lower than that of $H_2O$ (78.39), so ionic compounds are less soluble in it; ordinary water is the more effective solvent.
Hence the correct statements are a and b.