The Concentration of Odium Hydroxide Solution by Titration Against the Primary Standard Ethanedioic Acid-2-Water
Introduction
Titration is a method of analysis that to determine the precise
endpoint of a reaction. In a titration, solution was run from a
burette into a definite volume of another solution in a conical flask.
1 or 2 drops od suitable indicator (phenolphthalein) is added to
indicate the end point. The end point is the stage at which two
solutions have just reacted completely. The accuracy of titration
results depends very much on the correct detection of the end point.
Chemicals:
Ethanedioic acid-2-water crystals
Dilute sodium hydroxide solution
Phenolphthalein
Deionized water
Apparatus:
Beakers (100 cm3 ) x 4
Conical flasks (250 cm3 )
Pipette (25.0 cm3 )
Pipette filler
Burette (50.0 cm3 )
Stand and clamp
Volumetric flask (250.0cm3 )
Wash bottle
White tile
Glass rod
Weighing bottle
Electronic balance
Stopper
Chemical Reaction involved:
Procedures:
1. Clean all the glassware involved in this experiment (e.g. burette,
pipette, conical flasks, weighing bottle, volumetric flask, etc.) with
deionized water as directed by the teacher.
2. Weigh by difference to collect the required mass (2 to 2.5g) of
ethanedioic acid-2-water crystals.
3. Pour the weighed crystals into a dry clean 100 cm³ beaker and add
deinoized water to dissolve the crystals.
4. Wash the weighing bottle with deionized water and pour the rinse
into the bea...
... middle of paper ...
... usually placed in
the conical flask.
Improvements:
1. Graduation mark of pipette and volumetric flask should be
accurately reached.
2. Just add enough indicator solutions, not too much.
3. Ensure stopcock has been closed before filling.
4. Remember to fill up the tip of burette.
5. Fix the filled burette perfectly vertical.
6. Stopcock should be controlled by thumb, first and second fingers of
left hand
7. Swing the flask gently and continuously.
8. Slow down the adding of solution when end-point is close.
9. There should be no hanging drop of solution on the tip.
10. The spectula should be put back the original place, to prevent the
ethanedioic acid-2-water be contaminated.
Conclusion:
The concentration of sodium hydroxide calculated is 0.137M (correct to
3 sig. fig.)