Hello!
The pH of a buffer that consists of 0,45 M CH₃COOH and 0,35 M CH₃COONa can be calculated using the Henderson-Hasselbach equation. To input the values into this equation, we'll need the pKa of CH₃COOH, which can be found in tables. This value is 4,75. The Henderson-Hasselbach equation is as follows:
[tex]pH=pKa + log( \frac{[A^{-} ]}{[HA]} ) \\ pH=4,75 + log( \frac{0,35 M}{0,45M} ) \\ pH=4,64[/tex]
So, the pH of such buffer would be 4,64.
Have a nice day!