Calculate the ph of a buffer solution that contains 0.25 m benzoic acid (c6h5co2h) and 0.15 m sodium benzoate (c6h5coona). (ka = 6.5 × 10–5 for benzoic acid)

Respuesta :

Hello!

To solve this problem we'll use the Henderson-Hasselbach equation, but first we need the vale for the pKa of Benzoic acid, which is pKa= -log(Ka)=4,19

Now, we apply the equation as follows:

[tex]pH=pKa + log ( \frac{[C_6H_5COONa]}{[C_6H_5COOH]} )=4,19+log( \frac{0,15M}{0,25M} )=3,97 [/tex]

So, the pH of this solution of Sodium Benzoate and Benzoic Acid is 3,97

Have a nice day!