At `30^(@)C` dry air `[75 % N_(2)+25 % O_(2)]` is placed over `H_(2)O(l)` at 800 torr (combined pressure of all 3 gases). If pressure is gradually increased isothermally to 1560 torr, then calculate partial pressure of `O_(2)` at this pressure in torr.
`[VP_(H_(2)O)=50 "torr at"30^(@)C]`