the hydronium ion concentration of a 0.050 M solution of a weak acid is 5.9 X 10^-3 M. the acid-dissociation constant is 1.37 X 10^-4 at 25 celsius. what is the pH of this solution?

A. 0.077
B. 1.30
C. 2.23
D. 3.86
E. 5.13

You don't need most of the numbers.

pH = -log(H^+).

To find the pH of a solution, you need to calculate the negative logarithm (base 10) of the hydronium ion concentration. Here are the steps to find the pH of the given solution:

Step 1: First, calculate the concentration of the hydronium ion (H3O+) in the solution. In this case, the hydronium ion concentration is given as 5.9 × 10^-3 M.

Step 2: Take the negative logarithm (base 10) of the hydronium ion concentration:
pH = -log[H3O+]

Step 3: Substitute the value of hydronium ion concentration into the equation:
pH = -log(5.9 × 10^-3)

Step 4: Calculate the pH using a calculator:
pH ≈ 2.23

Therefore, the pH of the given solution is approximately 2.23.

Thus, the correct answer is option C. 2.23.