RP9-pH changes (ethanoic acid, sodium hydroxide)

• Equipment: burette, beaker, pH probe, stirring rod, ethanoic acid, sodium hydroxide.
• Set up: Calibrate the pH probe then rinse with deionised water. Pour 20 cm^3 of ethanoic acid into a beaker and rinse and fill a burette with sodium hydroxide.
• Method: Record the initial pH and rinse the probe with deionised water. Add 2 cm^3 sodium hydroxide and stir and repeat until near the endpoint. At that point, add in 0.2 cm^3 intervals. After, add in 2 cm^3 intervals again until the sodium hydroxide is in excess.
• Graph: Plot a graph of corrected pH values on the y axis and volume of sodium hydroxide added on the x axis.
• Analysis: Use a calibration curve to find the corrected pH measures from the readings given by the pH meter.