Among aqueous 1 N solutions, the pH of HCl , $\mathrm{HNO}_2$ and $\mathrm{CH}_3 \mathrm{COOH}$ follows the order

30 mL of 0.1 M acetic acid is mixed with 60 mL of 0.1 M sodium acetate. If $K_a=1.8 \times 10^{-5}$ what will be the pH of the solution?

The pH of 1 N aqueous solutions of HCl , $ \mathrm{CH}_{3} \mathrm{COOH} $ and HCOOH follows the order:

20 mL of 0.1 M acetic acid is mixed with 50 mL of potassium acetate. $ K_{\alpha} $ of acetic acid $ =1.8 \times 10^{-5} $ at $ 27^{\circ} \mathrm{C} $. Calculate the concentration of potassium acetate if pH of mixture is 4.8 .