Use the Henderson–Hasselbalch equation to calculate the pH of each solution
a solution that is 12.5 g of HF and 24.5 g of NaF in 125 mL of solution Express your answer using two decimal places.
Volume of the solution = 125mL = 0.125L
mass of HF= 12.5 grams
molar mass of HF = 20.01gram/mole
number of moles = mass/volume = 12.5/20.01 = 0.625 moles
concentration of HF = number of moles/volume = 0.625/0.125 =5.0M
[HF] = 5.0M
mass of NaF = 24.5 grasm
molar mass of NaF = 41.99 gram/mole
number of moles of NaF = 24.5/41.99 = 0.583 moles
concentration of NaF = 0.583/0.125 = 4.664 M
[NaF] = 4.664 M
Ka of HF = 6.6x10^-4
-log(Ka) = -log(6.6x10^-4)
PKa = 3.18
PH=PKa +log[NaF]/[HF]
PH = 3.18 +log(4.664/5.0]
PH = 3.149
PH = 3.15
Use the Henderson–Hasselbalch equation to calculate the pH of each solution a solution that is 12.5...