If `Delta _(f) G ^(@) (H_(2)O, l) = - 237 . 19 kJ mol ^(-1)` and `Delta _(f) G ^(@) (H _(2)O. g) =- 228.59 kJ mol ^(-1),` the vapour pressure of water at 298 K would be about

Options

A. 0.01 atm
B. 0.02 atm
C. 0.03 atm
D. 0.05 atm

Explanation

`Delta _(f) G ^(@) ( H_(2) O , g) - Delta _(r) G ^(@) ( H _(2) O , l ) = ( - 228. 59 + 237. 19) kJ mol ^(-1) = 8. 6 kJ mol ^(-1)`
`P _( H_(2) O (g)) //atm = K ^(@) =` antilog `( -Delta G ^(@) // 2. 303 RT)`
= antilog `{-8.6 xx 10 ^(3) // (2.303 xx 8. 314 xx 298)} = ` antilog `( - 1. 507) = 0.03`