Answer
$pH = 7.471$
Work Step by Step
1. Calculate the pKa value for the acid:
$pKa = -log(Ka)$
$pKa = -log( 2.9 \times 10^{- 8})$
$pKa = 7.538$
2. Using the Henderson–Hasselbalch equation:
$pH = pKa + log(\frac{[Base]}{[Acid]})$
$pH = 7.538 + log(\frac{0.150}{0.175})$
$pH = 7.538 + log(0.857)$
$pH = 7.538 + -0.0669$
$pH = 7.471$
