Question

t-Lab questions Ka measuring pH* titration

4. How would the following affect the results?

a) The buret is dirty and drops of NaOH cling to the side walls of the buret as it is drained.

b)The buret is not rinsed with NaOH prior to filling.

c)The buret tip is not filled at the start of the titration.

d)20 mL of unknown acid are used instead of 10 mL.

e)The buret is not read at eye level. Explain.

f)The base is added too rapidly in the region of rapid pH change.

g) 100 mL of distilled water is used instead of 75 mL.

h)The original volume of base is not at 0.00 mL and a student assumes it is.

5. Why is it important that if the acid solutions were heated, you allow them to cool to room temperature before titrating? What may be affected by temperature?

**please type answers or make it very easy to read, thank you

Answer 1

a) Undesired and uncalculated additional amount of NaOH can enter during titration.

b) impurities other than NaOH might be present in buret which can affect the titration.

c) There will be calculation error for the amount of NaOH added for about 1 ml

d) undesirable results will be obtained.

e) It will lead to paralax error.

f) Color will change immediately and excess NaOH will enter in the system. This will lead to wrong results.

g) Not enough data provided for this question.

h)If the student assumes present level as zero point, there is no problem in that.

5)The rate of rection and other physical properties might be affected with change in temperature. But the amount of NaOH required will still remain same until some byproduct is not formed at higher temperature.