Question

The Ka for benzoic acid is 6.5 × 10−5. Calculate the pH of a 0.14 M benzoic acid solution.

Answer 1

Answer:

2.52

Explanation:

C6H5COOH + H2O ⇄ C6H5COO- + H30+

 0.14M                                0                   0

  -X                                     +X                  +X

---------------------------------------------------------------

0.14-X                                   X                    X

Ka= 6.5 × 10^-5 = $\frac{x^{2} }{0.14-x}$  

Since the effect of X in equation (0.14-x) is very small, it can be ignored.

x= 3.02 × 10^-3

-logx = 2.52