Learning Basic Operations:
The Effect of pH on a Food Preservative

Hypothesis:
A test on if food preservatives react with human stomach acid was conducted to see if it was harmful or ineffective. The preservative tested was sodium benzoate. Sodium benzoate is a common food preservative used in food products such as jams, soft drinks, pickles, etc. and in tinned products in the food market. This experiment is aimed to determine whether benzoic acid is formed from its soluble form sodium benzoate in stomach acid. It is assumed that the harmful benzoic acid will be formed.

Method:
Sodium Benzoate (2.001 g) was combined with distilled water (10 g) by stirring. The sodium benzoate dissolved in the water. Approximately 3 mL 3M hydrochloric acid was added to the mixture, and a white precipitate was formed. Note that the pH should be less than 3. The mixture was then cooled to approximately 10.3◦C. The aqueous solution was then separated from the precipitate by using a vacuum. The precipitate was also washed with distilled water (5 mL) to ensure the purest precipitate possible. The vacuum continuously ran for five minutes to air dry. Afterwards, a very solid white powder was left in the spout of the vacuum. A vial was weighed (21.366g), and the white powder was then placed into the vial to be put in the oven to help dry. It was dried with a temperature range of 77oC-88oC. After a constant weight was achieved, the vial was weighed again (22.836g). The white powder acquired a weight of 1.17g.

Results:
2.001 sodium benzoate is dissolved with 10.00 mL of water to be a relatively clear mixture. 15 drops of hydrochloric acid was added to the mixture. A white cloudy precipitate was formed. After the mixture was