Answer:
[tex]pH=3.97[/tex]
Explanation:
Hello,
In this case, for the calculation of the pH of the given buffer we need to use the Henderson-Hasselbach equation:
[tex]pH=pKa+log(\frac{[base]}{[acid]} )[/tex]
Whereas the pKa for benzoic acid is 4.19, the concentration of the base is 0.15 M (sodium benzoate) and the concentration of the acid is 0.25 M (benzoic acid), therefore, the pH turns out:
[tex]pH=4.19+log(\frac{0.15M}{0.25M} )\\\\pH=3.97[/tex]
Regards.
