Question

5. (2pts) To calculate the pH of buffer solution we need to use Henderson-Hasselbalch equation The generic form of this equation is: 6. (8 points) What is the pH of a solution that contains 25 ml of 0.10 M HF and 25 ml 0.1M NaOH solution? (Ka of HF -6.8 x 104).

Answer 1

HAF H20A-FH20 Acid C.B eq? is : PH Epla THA] 6) mmed Hfz cmentatein x volumelin mi) - 25 mixo.1M= 2.5mmal mmola Na Cl =001825=2.5 mmol So, its equivalence point asmole daied = mole d bace - mmol df formed = 2.5 [f.] = 2.5 mmol = 0.05m F + H₂O EHF four I 0.05 c -x fx te E o.os-a n a ne 0.05-1 YO.05 som POH ko= K Eb- = al losun 0.05 - 1. x2 E-Px 164 = 0.05 > a= 8.575x 10-7M pH=14-polla 14+ lopx = 7.93