Question

Part A: Standardization of NaOH Solution Data Table: Trial 1 Trial 2 Trial 3 Tared mass of KHP (g) 5065 -S168 so40 Molar mass of KHP (g/mol) 204.23 204.23 204.23 Moles of KHP (mol) Buret Reading:Initial Volume of NaOH (mL) .3 23. 2 나6.2. Buret Reading: Final Volume of NaOH (mL) Volume of NaOH dispensed (mL) Molar concentration of NaOH (mol/L) Average Molar concentration of NaOH 28.3 22.1 1145 O533 ces 3 (mol/L) Experiment: Volumetric Analvsis

Answer 1

Answers to the Post-lab questions.

1. If the KHP is not completely dry, the weighted mas will not correspond to the actual amount of substance KHP. As a result, less NaOH will be required to neutralize the same mass of wet KHP, and the calculated concentration of NaOH will be greater than the actual concentration.

2.The mass of KHP was measured precisely in order to obtain the reliable number for the amount of substance. The volume of added water does not matter, since it will not change the amount of KHP to be titrated with NaOH. The volume of KHP solution is not to be measured, as the amount of substance is independent from the degree of dilution.

3. The first type fo error is the indicator or instrumental error, it arises from the way of the equivalence point determination. This error can be either positive or negative (corresponding to the undertitrated or overtitrated solution).

The second type of error goes from the volume measurment using a burette (air in the stopcock, buret tip, parallax error). The sign of each of these errors in unpredictable as well - they can be positive or negative.

Another very critical error is the error in determination of NaOH concentration, as it is used as a standard solution. Therefore, any uncertainty in NaOH concentration leads to uncertainty in HCl concentration.