Answer: Slightly lower (~78 vs 80) because D 2 O hydrogen bonds are slightly stronger making it less polarisable.
- A Slightly lower (~78 vs 80) because D<sub>2</sub>O hydrogen bonds are slightly stronger making it less polarisable
- B Noticeably higher than ordinary water mainly because of its greater molecular mass during normal conditions
- C Exactly the same numerical value as ordinary water since both share identical polarity as generally observed
- D Much lower, falling below 20, supposedly due to unusually weak deuterium bonding in typical laboratory settings
Correct answer: A. Slightly lower (~78 vs 80) because D<sub>2</sub>O hydrogen bonds are slightly stronger making it less polarisable
Explanation: D<sub>2</sub>O has slightly stronger O-D...O hydrogen bonds than O-H...O, making the structure more rigid and slightly less polarisable.
Each water molecule's O-H bonds (covalent, solid) can hydrogen-bond (dashed) to neighbouring molecules, forming an extended network responsible for water's unusually high boiling point and density anomaly.
Concept context
The simplest and most abundant element in the universe. Study its unique position in the periodic table, isotopes (protium, deuterium, tritium), properties of water and hydrogen peroxide, and industrial uses.