What Is the Concentration of O₂(g) in Water at 25 ^$\circ$

Multiple Choice

What is the concentration of O₂(g) in water at 25 ^$\circ$ C exposed to a partial pressure of oxygen of 325 mmHg The Henry's law constant for oxygen gas at 25 ^$\circ$ C is 1.3 * 10^-3 mol/L·atm.

A) 1.6 * 10^-4 M
B) 3.6 * 10^-4 M
C) 5.6 * 10^-4 M
D) 7.6 * 10^-4 M
E) None of the above