Lemon Juice Titration

Introduction

The technique utilized in this experiment was titration and is used to determine the concentration of an unknown solution by reacting with a known concentration of solution. In a titration, the titrant is placed into the burette and the analyte delivered into the conical flask using a pipette. Titration involves adding a small amount of titrant slowly to the analyte to achieve the equivalence point. The equivalence point is when the moles of the standard solution are same as the solution of unknown concentration and is produced at a pH of 7. The indicator used in this experiment was Phenolphthalein which determined the endpoint in a form of colour change. In this experiment, citric acid was titrated with sodium hydroxide producing an endpoint between pH range of 8.3-10. (EASYCHEM, 2018) Citric acid has three acidic protons, therefore, it is a triprotic acid (lumen, 2018). The accurate concentration of the sodium hydroxide must be known to determine the citric acid concentration. The aim of this experiment was to determine the citric acid (weak acid) content of Lemon Juice by titrating it with standard sodium hydroxide solution (strong base). A commercially available lemon juice has a concentration of around 34.1 to 48.0 g/L (0.177 to 0.249 mol/L) of citric acid (Penniston, 2008). It was

The ordinary pipette used in this experiment should be replaced with an automatic pipette. Automatic pipette can be utilised to transfer small volumes of solution accurately. Another improvement which can make a difference in precision is an analytical balance to weigh out the mass of a substance accurately, because the scale is surrounded by a barrier and therefore decreases air resistance. While reading the burette, it was difficult to recognise the bottom of the meniscus and could have been easily recognised if a white piece of paper was held behind the