Use the Henderson Hasselbach equation to determine how much sodium formate (HCOONa, 68.0069 g/mol) should be added to 400 ml of 1M formic acid to make this buffer have a pH = 3.500. (Ka = 1.77 x 10^-4)

A buffer solution contains 0.285 M hydrofluoric acid and 0.326 M potassium fluoride. If 0.0252 moles of hydroiodic acid are added to 225 mL of this buffer, what is the pH of the resulting solution ? (Assume that the volume change does not change upon adding hydroiodic acid) Ka of HF= 7.2x10^-4pH=

What quantity in moles of CH₃NH₃Cl  need to be added to 200.0 mL of a 0.500 M solution of CH₃NH₂ (Kb for CH₃NH₂ is 4.4 × 10⁻⁴) to make a buffer with a pH of 11.00?

a) Determine the mass (in grams) of sodium formate that must be added to 1.00 L of 0.180 M formic acid to prepare a buffer with a pH = 3.50. Assume there is no change in volume upon addition of the sodium formate. b) Write the predominant chemical reaction that occurs when 0.050 mol of HClO4 is added to 1.00 L of the buffer prepared in part a and calculate the pH of the solution.