1) A solution of citric acid, C3H5O(COOH)3 , was analysed by titration. 25.0 mL aliquots of the C3H5O(COOH)3 solution were titrated against a standardised solution of 0.0250 M sodium hydroxide, NaOH. Phenolphthalein indicator was used and the average titre was found to be 24.0 mL
a. Based on the titration, the concentration of C3H5O(COOH)3 in the solution was
A. 8.0 × 10−3 M
B. 8.7 × 10−3 M
C. 2.6 × 10−2 M
D. 7.2 × 10−2 M
Solution
b. Which one of the following would have resulted in a concentration that is higher than the actual concentration?
A. The pipette was rinsed with NaOH solution.
B. The pipette was rinsed with C3H5O(COOH)3 solution.
C. The conical flask was rinsed with NaOH solution.
D. The conical flask was rinsed with C3H5O(COOH)3 solution
Solution