To determine the percentage of free alkali in the soap sample.
Burette,beaker,conical flask, titration flask, measuring cylinder, funnel.
* Soap sample
* 0.01 M HCl
* Phenolphthalein indicator
Weigh out 10g of foundry soap and transfer it into a beaker containing 150 ml of distilled water. Warm the beaker to dissolve soap for 30 to 40 ...view middle of the document...
Add more distilled water to make up to 250 ml mark. Don't shake the flask otherwise foam will be produced which may give wrong results.
Take 10 ml of the soap solution in the titration flask. Add two drops of phenolphthalein indicator in the titration flask, color will change into pink. Titrate it against 0.01M HCl from the burette, until the solution turn colorless.
Take three readings and calculate its mean.
Initial Reading | Final Reading | Difference | Mean Volume |
0 0 0 | 2.7 2.9 2.6 | 2.7 2.9 2.6 | 2.73 |
Observation And Calculations:
Amount of NaOH in g/L= 0.00273×40
Amount of NaOH in g/L= 0.1092g/L
Amount in g in 1000 ml of sample= 0.1092g
Amount in g in 1 ml of sample= 0.1092/1000
Amount in g in 250 ml of sample= 0.1092×250/1000
Percentage Alkalinity=0.0273×100/10= 0.27%