Use the following data to calculate the molarity of the sodium hydroxide solutio
ID: 1005010 • Letter: U
Question
Use the following data to calculate the molarity of the sodium hydroxide solution. Show your calculations clearly. The molar mass of KHP = 204.22 g/mol. The following data represent data from the two best runs. You should calculate the % difference between the 2 results Determination of the molarity of a Polyprotic Acid. The standardized base form is used to determine the molarity of an polyprotic acid. A 15.00 mL sample of acid is titrated with the standard base. If the buret readings are V = 0.25 mL and V_= 30.15 mL, what is the concentration of the unknown acid if its structure is? HA H_2 A H_3 AExplanation / Answer
part A
KHP + NaOH ----> KNaP + H2O
M1V1 = M2V2
trail 1 : buret reading = 14.95-0.00 = 14.95 ml
No of mol of KHP = (0.7549/204.22) = 0.00373 mol
No of mol of NaOH consumed = 0.00373 mol
concentration of NaOH = 0.00373/0.01495 = 0.2494 M
trail 2
buret reading = 29.7-14.95 = 14.75 ml
No of mol of KHP = (0.7621/204.22) = 0.00369 mol
No of mol of NaOH consumed = 0.00369 mol
concentration of NaOH = 0.00369/0.01475 = 0.2501 M
% difference between two 2 results = 0.28%
part B
1. M1V1/n1 = M2V2/n2
volume of NaOH = 30.15 - 0.25 = 29.9 ml
(0.25*29.9/1) = (M2*15/1)
[HA] = 0.498 M
2. H2A
volume of NaOH = 30.15 - 0.25 = 29.9 ml
(0.25*29.9/2) = (M2*15/1)
[H2A] = 0.249 M
3. H3A
volume of NaOH = 30.15 - 0.25 = 29.9 ml
(0.25*29.9/3) = (M2*15/1)
[H3A] = 0.166 M