A 0.180 M solution of a weak acid (HA) has a pH of 2.96. Calculate the acid-dissociation constant (Ka) for the acid. Express your answer to two significant figures.
16. Consider the titration of a 23.0-mL sample of 0.110 M HC2H3O3 (Ka=1.8×10^−5) with 0.130 M NaOH. Determine the pH after adding 6.00 mL of base beyond the equivalence point. Express your answer to two decimal places.
15. Consider the titration of a 36.0 mL sample of 0.175 M HBr with 0.205 M KOH. Determine each of the following:
a. the pH at 11.1 mL of added base. Express your answer using three decimal places.
b. the pH at the equivalence point. Express your answer as a whole number.
11. For 280.0 mL of pure water, calculate the initial pH and the final pH after adding 0.028 mol of NaOH. Express your answers to two decimal places. Enter your answers numerically separated by a comma.
For 280.0 mL of a buffer solution that is 0.225 M in HCHO2 and 0.300 M in KCHO2, calculate the initial pH and the final pH after adding 0.028 mol of NaOH. (Ka(HCHO2)=1.8×10^−4.) Express your answers to two decimal places. Enter your answers numerically separated by a comma.
For 280.0 mL of a buffer solution that is 0.295 M in CH3CH2NH2 and 0.225 M in CH3CH2NH3Cl, calculate the initial pH and the final pH after adding 0.028 mol of NaOH. (Kb(CH3CH2NH2)=5.6×10^−4.) Express your answers to two decimal places. Enter your answers numerically separated by a comma.