Which of these correctly defines thepOH\mathrm{pOH}pOHof a solution?

Step 1: Define the Problem

Identify the key components of the question that need to be addressed:

• Determine the correct definition of pOH for a solution.

Step 2: Break Down the Problem

Divide the problem into smaller, manageable parts:

• Understand the concept of pOH.
• Relate it to the concentration of hydroxide ions in a solution.

Step 3: Apply Relevant Concepts

Use appropriate academic theories or formulas to solve each part of the problem:

• pOH is a measure of the hydroxide ion concentration in a solution.
• It is defined mathematically as:
  $\text{pOH} = -\log_{10}[\text{OH}^-]$ where $[\text{OH}^-]$ is the concentration of hydroxide ions in moles per liter.

Step 4: Analysis, Verify and Summarize

Analyze each part in detail if necessary, carry out the calculations by steps. Verify the calculations result and summarize the findings:

• The pOH scale is used to express the alkalinity of a solution.
• It is related to the pH scale by the equation:
  $\text{pH} + \text{pOH} = 14$ at 25°C.

Final Answer

The pOH of a solution is defined as the negative logarithm (base 10) of the hydroxide ion concentration:
$\text{pOH} = -\log_{10}[\text{OH}^-]$