Question

Calculate the ph of a 0.200 m hcl solution at 25°C

A. pH = 0.699 POH = 13.30
B. pH = 0.400 pOH = 13.60
C. pH = 3.699 pOH = 17.30
D.pH = 0.200 pOH = 13.80

Answer 1

The correct pH of a 0.200 M HCl solution at 25 °C is 0.699, and the correct pOH is 13.301, making option A the correct answer (pH = 0.699, pOH = 13.30).

Step-by-step explanation:

Calculating pH and pOH of Solutions

To calculate the pH of a 0.200 M HCl solution at 25 °C, we can use the formula pH = -log[H3O+]. For a strong acid like HCl, which ionizes completely, the concentration of H3O+ ions is equal to the concentration of the acid. Thus, pH = -log(0.200), resulting in a pH of 0.699. Correspondingly, the pOH can be calculated using the relationship pOH = 14.00 - pH, which gives us pOH = 13.301. Therefore, the correct answer to the student's question is A. pH = 0.699 and pOH = 13.30.

We can similarly calculate the pH and pOH for other solutions given their concentrations and knowing whether they are acids or bases, by using the ionization property of the substances and the corresponding relationship between hydronium and hydroxide ions.