10. A solution contains a mixture of 0.207 M formic acid (HCOOH) and 0.248 M sodium formate (HCOONa).The solution volume is 1.25 L. The Ka of HCOOH = 1.8 x

10^-4. a) (2 marks) What is the pH of this solution? b) (2 marks) What is the pH of this solution after 2.5 grams of formic acid have been added to it? c) (2 marks) What will be the pH of this solution if 50 mmol of HBr is added to the solution in part (a)?