Final answer:
The pH of a 5 x 10⁻⁴ M HCl solution is calculated by taking the negative logarithm (-log) of the hydronium ion concentration, which is equal to the acid concentration. The calculation is straightforward using a calculator's logarithmic function.
Step-by-step explanation:
To calculate the pH of a 5 x 10⁻⁴ M HCl solution, we use the formula pH = -log[H3O+], where [H3O+] is the concentration of hydronium ions. Since hydrochloric acid (HCl) is a strong acid, it dissociates completely in water, implying that the concentration of hydronium ions, [H3O+], is equal to the concentration of HCl.
Therefore, the pH is calculated as follows:
pH = -log[5 x 10⁻⁴]
Using a calculator:
- Enter the concentration (5 x 10⁻⁴) into the calculator.
- Press the "log" button.
- Press the "+/-" button to make it negative.
- The displayed result will be the pH of the solution.
Calculating pH with this method is straightforward, and using the logarithmic function on a calculator simplifies the process. The antilog function or 10^ button may also be used to find the concentration of hydronium ions if the pH is known.