Question

The pOH value of a solution whose hydroxide ion concentration is \( 6.2 \times 10^{-9} \, \text{mol/litre} \) is:

• A. 8.21
• B. 6.21
• C. 7.75
• D. 7.21

Hint:

To find pOH, take the negative logarithm of the hydroxide ion concentration.

Answer 1

The Correct Option is A

Step 1: pOH and concentration relation.
The pOH is related to the hydroxide ion concentration \( [OH^-] \) by the equation: \[ \text{pOH} = -\log [OH^-] \] Substituting the given concentration \( 6.2 \times 10^{-9} \, \text{mol/litre} \), we get: \[ \text{pOH} = -\log (6.2 \times 10^{-9}) = 8.21 \] Thus, the correct answer is (1).