Toothpaste Titration Essay

1.1 Procedure

To determine the percentage of Calcium carbonate (CaCO3 ) in a given toothpaste sample, containing CaCO3,back titration is carried out using 0.16M of hydrochloric acid(HCl) and 0.08M of sodium hydroxide (NaOH).

First, 10ml of standard HCI solution was drawn using a transfer pipette. Certify that the meniscus was read correctly. The drawn solution of 0.16M of standard HCl was then pipetted into a clean conical flask, that was prepared by washing with distilled water. Any droplets of HCI suspending from the pipette tip was removed by tapping against the inner walls of mouth of the conical flask. The remaining solution in the pipette tip was not meant to be forced out as that have already been taken into consideration when the pipette was made.

Secondly, the container containing the

As there is no aqueous solution of toothpaste, titration cannot be carried out. In this experiment, back titration is carried out such that the chemical reactions involved are rapid, stochiometric, quantitative and no side reaction.

In the experiment, a glass funnel was inserted into the conical flask while heating the solution. The rationale of adding the glass funnel to the setup is to prevent a build-up of carbon dioxide in the flask while keeping the amount of solution evaporated to a minimum. This is because calcium carbonate undergoes thermal decomposition during heating to produce calcium oxide and carbon dioxide.

However, there is a moderate degree of accuracy to the results obtained from back titration due to a combination of systematic and random errors. Systematic errors are errors such as personal, method and instrument errors. The greatest contribution of error is due to the judgement of the colour of the solution when the end point of the titration is