What is the pH of a solution prepared by mixing 30.00 mL of 0.10 MCH3CO2H with 30.00 mL of 0.030 MCH3CO2K? Assume that the volume of the solutions are additive and that Ka=1.8×10−5 for CH3CO2H.

Answer : The  pH of the solution is, 4.2

Explanation : Given,

Concentration of = 0.10 M

Concentration of = 0.030 M

First we have to calculate the value of .

The expression used for the calculation of is,

Now put the value of in this expression, we get:

Now we have to calculate the pH of buffer.

Using Henderson Hesselbach equation :

Now put all the given values in this expression, we get:

Therefore, the pH of the solution is, 4.2

93.2 ml + 3920 ml = 4013 ml total  

(93.2 ml) * (2.03 m) / (4013 ml) = 0.0471 m

the volume in in l of the diluted solution would be 0.0471 m.

the answers would be

the first one and the second one