Equilibrium constants are given (in atm) for the following reactions at `0^(@)C` :
`SrCl_2 . 6H_2O(s) hArr SrCl_2 . 2H_2O(s)+4H_2O(g) K_p=5xx10^(-12)`
`Na_2HPO_4 . 7H_2O(s)+5H_2O(g) K_p=2.43xx10^(-13)`
`Na_2SO_4 . 10H_2O(s) hArr Na_2SO_4(s)+10H_2O(g) K_p=1.024xx10^(-27)`
The vapour pressure of water at `0^@C` is 4.56 torr.
Which is the most effective drying agent at `0^@C` ?

Options

A. `SrCl_2 . 2H_2O`
B. `Na_HPO_4 . 7H_2O`
C. `Na_2SO_4`
D. All equally

Answer

A