Can you please explain how Calculate the pH of a solution t

Can you please explain how ?

Calculate the pH of a solution that contains 0.10 M propionic acid, CH3CH2COOH, and 0.05 M sodium propionate, CH3CH2COONa. For CH3CH2COOH, pKa 4.9. 15. a)5.2 b) 4.9 c) 4.6 d 43

Solution

15.

    [CH3CH2COOH] = 0.1M

[CH3CH2COONa] = 0.05M

PKa = 4.9

PH = PKa + log[CH3CH2COONa]/[CH3CH2COOH]

         = 4.9 + log0.05/0.1

        = 4.9-0.3010   = 4.6

c. 4.6 >>>>answer