A BS Medical Technology student was asked to determine the molecular weight of a diprotic acid using acid-base titration. This student performed four trials. Firstly, the student used potassium hydrogen phthalate (KHP, 204.22 g/mol) as standard to determine the exact concentration of the NaOH titrant. The results of the student are summarized in the table below: Note: The stoichiometric relationship of KHP to NaOH is 1:1 Standardization Trial 1 Trial 2 Trial 3 Trial 4 KHP Mass, g 0.5033 0.5066 0.6989 0.6843 Volume NaOH used, mL 24.32 25.61 24.67 24.56 After the standardization, the student weighed different amounts of the unknown acid. In a similar fashion, the student performed acid-base titration using phenolphthalein as indicator. The results of the molecular weight determination are summarized below: Note: The stoichiometric relationship of Unknown acid to NaOH is 1:2 Molecular Weight Determination Trial 1 Trial 2 Trial 3 Trial 4 Unknown Mass, g 0.1234 0.1034 0.1178 0.1322 Volume NaOH used, mL 21.75 20.56 24.39 25.08 The potential unknown given by the professor to the student are as follows: Diprotic acid Fumaric acid Oxalic acid Succinic acid Malonic acid Tartaric acid Citric acid Molecular Weight, g/mol 116.07 90.03 118.09 104.06 150.09 192.12 45. What is the molarity of NaOH solution at the standardization procedure in Trial 1? A) 0.1387 B) 0.0969 C) 0.1013 D) 0.1364 E) 0.1183 46. What is the molarity of NaOH solution at the standardization procedure in Trial 2? A) 0.1387 B) 0.0969 C) 0.1013 D) 0.1364 E) 0.1183 47. What is the average molarity of NaOH solution at the standardization procedure? A) 0.1387 B) 0.0969 C) 0.1013 D) 0.1364 E) 0.1183
A BS Medical Technology student was asked to determine the molecular weight of a diprotic acid using
trials. Firstly, the student used potassium hydrogen phthalate (KHP, 204.22 g/mol) as standard to determine the exact concentration of the NaOH
titrant. The results of the student are summarized in the table below:
Note: The stoichiometric relationship of KHP to NaOH is 1:1
Standardization Trial 1 Trial 2 Trial 3 Trial 4
KHP Mass, g 0.5033 0.5066 0.6989 0.6843
Volume NaOH used, mL 24.32 25.61 24.67 24.56
After the standardization, the student weighed different amounts of the unknown acid. In a similar fashion, the student performed acid-base titration
using phenolphthalein as indicator. The results of the molecular weight determination are summarized below:
Note: The stoichiometric relationship of Unknown acid to NaOH is 1:2
Molecular Weight
Determination
Trial 1 Trial 2 Trial 3 Trial 4
Unknown Mass, g 0.1234 0.1034 0.1178 0.1322
Volume NaOH used, mL 21.75 20.56 24.39 25.08
The potential unknown given by the professor to the student are as follows:
Diprotic acid Fumaric acid Oxalic acid Succinic acid Malonic acid Tartaric acid Citric acid
Molecular Weight,
g/mol
116.07 90.03 118.09 104.06 150.09 192.12
45. What is the molarity of NaOH solution at the standardization procedure in Trial 1?
A) 0.1387
B) 0.0969
C) 0.1013
D) 0.1364
E) 0.1183
46. What is the molarity of NaOH solution at the standardization procedure in Trial 2?
A) 0.1387
B) 0.0969
C) 0.1013
D) 0.1364
E) 0.1183
47. What is the average molarity of NaOH solution at the standardization procedure?
A) 0.1387
B) 0.0969
C) 0.1013
D) 0.1364
E) 0.1183
48. How many moles of diprotic acid have reacted in the molecular weight determination step for Trial 3?
A) 0.0011
B) 0.0012
C) 0.0013
D) 0.0014
E) 0.0015
49. Considering all the trials in molecular weight determination, what is the average molecular weight of the acid as analyzed by the student?
A) 85.00
B) 87.90
C) 81.63
D) 89.09
E) 84.32
50. If the percent error of the student in his analysis was around 2.37%, what is the identity of the diprotic acid given to him?
A) Fumaric acid
B) Succinic acid
C) Tartaric acid
D) Oxalic acid
E) Malonic acid
Trending now
This is a popular solution!
Step by step
Solved in 6 steps with 6 images
