Final answer:
The pH of the resulting solution when 100 mL of 0.500 M hypochlorous acid is mixed with 100 mL water is 7.52.
Step-by-step explanation:
To find the pH of the resulting solution, we need to consider the dissociation of hypochlorous acid (HOCl) in water. The equation for the dissociation is:
HOCl ⇌ H⁺ + OCl⁻
The initial concentration of HOCl is 0.500 M, but since it is diluted with water, the final concentration will be different. However, since water does not affect the concentration of H⁺ ions, the concentration of H⁺ will remain the same. We can then use the equation:
pH = -log[H⁺]
To calculate the concentration of H⁺, we can use the equilibrium constant (Ka) and the initial concentration of HOCl:
Ka = [H⁺][OCl⁻] / [HOCl]
Since water is not included in the equilibrium expression, its concentration does not affect the value of Ka. Rearranging the equation, we get:
[H⁺] = Ka x [HOCl] / [OCl⁻]
Substituting the values, we have:
[H⁺] = (3.0 x 10⁻⁸) x (0.500 M) / (0.500 M)
[H⁺] = 3.0 x 10⁻⁸ M
Finally, taking the negative logarithm, we find:
pH = -log(3.0 x 10⁻⁸) = 7.52