Question

Which of the following statements is/are incorrect for diamond?
(a) The refractive index of diamond is highest among solids.
(b) Diamond is hard because all the valence electrons of each carbon atom are involved in bond formation.
(c) Diamond is thermodynamically more stable than graphite.
(d) One carat of diamond represents its weight.

• A. All are correct
• B. a, b and c
• C. a and b
• D. c only

Answer 1

Answer: (D)

c only

Graphite is thermodynamically more stable than diamond, diamond is kinetically stable thus statement c is incorrect.

Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. Carat is just a unit to represent its weight.

Diamond also possess an extremely high refractive index and fairly high dispersion.

Hence, the answer is option $\text{D}$