Answer :

To determine the pH of a 0.027 M KOH solution, we need to understand a few key concepts about pH and strong bases.

Step-by-Step Explanation:

  1. Understanding KOH as a Strong Base:

    • Potassium hydroxide (KOH) is a strong base. This means it dissociates completely in water into K⁺ ions and OH⁻ ions.
    • Therefore, the concentration of OH⁻ ions in the solution is equal to the concentration of KOH, which is 0.027 M.

  2. Calculating the pOH:

    • The pOH is calculated using the formula:
      [tex]\text{pOH} = -\log[\text{OH}^-][/tex]
    • Plug in the concentration of OH⁻ ions:
      [tex]\text{pOH} = -\log(0.027)[/tex]
    • Calculate:
      [tex]\text{pOH} \approx 1.57[/tex]

  3. Converting pOH to pH:

    • The relationship between pH and pOH is given by the equation:
      [tex]\text{pH} + \text{pOH} = 14[/tex]
    • From the calculated pOH:
      [tex]\text{pH} = 14 - 1.57[/tex]
      [tex]\text{pH} \approx 12.43[/tex]

Based on this calculation, the pH of a 0.027 M KOH solution is approximately 12.43.

Conclusion:

  • The correct answer is (c) 12.43.
  • This makes sense because KOH is a strong base, and we expect the pH to be greater than 7, which indicates a basic solution.

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