Final answer:
The pH and pOH values of the solutions can be calculated as the negative logarithm of their respective ion concentrations, and they ionize completely in water at 25 °C.
The correct answer is options c) 0.8 M HNO₃.
Step-by-step explanation:
At 25 °C, the pH is the negative logarithm of the hydrogen ion concentration ([H+]), and the pOH is the negative logarithm of the hydroxide ion concentration ([OH-]). In solutions where substances ionize completely, these values can be directly calculated using molarity. Here are the pH and pOH of given solutions:
2.0 M HCl: pH = -log(2.0) = 0.30, pOH = 14 - pH = 13.70
1.5 M NaOH: pOH = -log(1.5) = 0.18, pH = 14 - pOH = 13.82
0.8 M HNO3: pH = -log(0.8) = 0.10, pOH = 14 - pH = 13.90
1.2 M KOH: pOH = -log(1.2) = 0.08, pH = 14 - pOH = 13.92
The correct answer is options c) 0.8 M HNO₃.