The pH of $0.10 M$ $CH X_{3} COONa$ ( $K_{a} = 1.8 \times 1 0^{- 5}$ ) is calculated by the usual hydrolysis formula. The solution is now diluted to 100 times its volume with water. Assuming the same formula holds, the new pH is

Answer: D

pH = 7 + \frac{1}{2} (p K_{a} + lo g C)

. Initially

pH = 8.87

. A 100-fold dilution lowers

lo g C

by 2, so pH falls by 1:

pH = 7.87

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