Oxygen Gas Makes Up 21 % of the Atmosphere by Volume

Multiple Choice

Oxygen gas makes up 21 % of the atmosphere by volume. What is the solubility of O₂(g) in water at 25 ^$\circ$ C if the atmospheric pressure is 741 mmHg The Henry's law constant for oxygen gas at 25 ^$\circ$ C is 1.3 * 10^-3 mol/L·atm.

A) 2.7 * 10^-4 M
B) 1.3 * 10^-3 M
C) 6.2 * 10^-3 M
D) 9.6 * 10^-3 M
E) 0.96 M