The value of Henry's constant for CO2 gas dissolved in water at 290 K is 12.8 MPa. Consider water exposed to atmospheric air at 100 kPa that contains 3 percent CO2 by volume. Under phase equilibrium conditions, the mole fraction of CO2 gas dissolved in water at 290 K is
(a) 2.3 ×10-4
(b) 3.0 × 10-4
(c) 0.80 × 10-4
(d) 2.2 ×10-4
(e) 5.6 × 10-4