The b.p of `CF_(4)` is almost half that of `SiF_(4)` while the difference in b.p of `C Cl_(4) " and " SiCl_(4)` is little. This is because

Options

A. the negative charge on fluorine cause greater repulsion between neighbouring molecules in `CF_(4)` where as it is less in `SiF_(4)` due to back bonding form `F rarr Si`
B. in `SiCl_(4)` inter-molecular repulsions are more due to the negative charge chlorine as `pi` back bonding formed `Cl rarr Si` is
C. `C Cl` bonds in `C Cl_(4)` are less polar then `Si - Cl` bond in `SiCl_(4)`
D. All are correct

Answer

D