Calculate van der Waals constansts a and b if critical temperature and critical pressure are `30^(@)C` and 72 atm respectively .

Explanation

`T_(C) = (8a)/(27 Rb)` and `P_(C) = (a)/(27b^(2))`
`:. (T_(C))/(P_(C)) = (8b)/(R ) ` or `b = (RT_(C))/(8P_(C))`
`:. B = (0.0821 xx 303)/(8 xx 72) = 0.043 "litre mo1"^(-1)`
`a = 27P_(C) xx b^(2) = 27 xx 72 xx (0.043)^(2)`
`=3.59 litre^(2) "atm mo1"^(-2)` .