The melting point of `RbBr` is `682^(@)C`, while that of `NaF` is `988^(@)C` . The principla reason that melting point of `NaF` is much higher than that of `RbBr` is that `:`

Options

A. The two crystals are not isomorphous
B. The molar mass of NaF is smaller than that of RbBr
C. The internuclear distance, `r_(c) + r_(a)` is greater for RbBr than for NaF
D. The bond in RbBr has more covalent character than the bond in NaF

Answer

C