The correct order of the thermal stability of hydrogen halides `(H-X)` is

Options

A. `HI gt HCI lt HF gt HBr`
B. `HCI lt HF gt HBr lt HI`
C. `HF gt HCI gt HBr gt HI`
D. `HI gt HBr gt HCI gt HF`

Answer

C

Explanation

According to Fajans' rules polarisation of `e^(-)` density of `F` towards `H` is less as compared to `HBr ,HCI` and `HI` ltbr? Therefore thermal stability of `HF` is more than others The polarisation of `e^(-)` density of halide ion towards `H` increases with increase in size .