Hydrogen Bonding

Step 1: Understanding Heavy Water.
Heavy water (D O) is water in which both hydrogen atoms are replaced by deuterium, a heavier isotope of hydrogen. This slight difference in mass increases the boiling point compared to regular water (H O). The boiling point of heavy water is 101.4 C, while the boiling point of regular water is 100 C.

Step 2: Analyzing the options.
(A) 100.4 C: Incorrect. This is close to the boiling point of regular water, but not the boiling point of heavy water.
(B) 101.4 C: Correct. This is the correct boiling point of heavy water.
(C) 273 C: Incorrect. This is far too high and does not correspond to any known form of water.
(D) 100 C: Incorrect. This is the boiling point of regular water, not heavy water.

Step 3: Conclusion.
The boiling point of heavy water is 101.4 C, corresponding to option (B).