If Water Contains About 42 Mg of Oxygen Per Liter

Multiple Choice

If water contains about 42 mg of oxygen per liter at 20°C and 1.0 atm, what would be the value of Henry's law constant for oxygen dissolving in water? The mole fraction of oxygen in air is 0.21.

A) 0.25 mol/(L atm)
B) 1.3 *10^-3 mol/(L atm)
C) 1.9 *10^-2 mol/(L atm)
D) 6.3 * 10^-3 mol/(L atm)
E) 0.010 mol/(L atm)