An Acid – Base Titration
Aim: The purpose of this experiment is to determine the concentration of a solution of Sodium hydroxide by titration against a standard solution of Potassium hydrogenphtalate.
The Importance of phenolphthalein in this experiment: the phenolphthalein indicator is important in this experiment for the following reasons;
- It enables us to know the exact volume of the base needed to completely neutralize the solution of the acid.
- It shows when the neutralization has come to the end point by turning slightly pink in the acid.
- one can know that the neutralization has gone past the end point when the indicator turns darker pink
Color of acid before neutralization: Colorless liquid
Color of acid close to the end point: Colorless with frequent pink color that disappears
almost immediately as it is seen.
Color of acid at the end point: slightest shade of pink that does not disappear within one
Temperature of room: 26.2ºc
Color of Base: Colorless solution.
Color of phenolphthalein indicator before neutralization: Colorless liquid
Color of phenolphthalein indicator after neutralization: slightly pinkish
Table showing the number of trials performed in this experiment, the volume of the acid used, the volume of the base (NaOH) used, the number of phenolphthalein indicator drops used in each trial and the initial and final readings of the burette.
Calculations for Trial 1