Answer

Methodology: Titration of Vinegar Using Standardised Sodium Hydroxide Solution

A 25.0 mL aliquot of the unknown vinegar solution was pipetted into a 250 mL volumetric flask. The solution was then diluted to the calibration mark with deionised water and shaken thoroughly to ensure a uniform mixture.

A burette was filled with the standardised sodium hydroxide (NaOH) solution that had been prepared in a previous experiment. Care was taken to remove any air bubbles from the burette tip to ensure accurate volume delivery.

Three separate 250 mL conical flasks were each charged with a 25.0 mL aliquot of the diluted vinegar solution using a clean pipette. To each flask, approximately 25.0 mL of deionised water was added to maintain a manageable titration volume.

Between 4 to 6 drops of phenolphthalein indicator were introduced to each conical flask. The indicator served as a visual cue to identify the endpoint of the titration.

The titration was conducted by slowly adding the standardised NaOH solution from the burette to the acidic vinegar solution while continuously swirling the flask. The titration was stopped upon the appearance of the first permanent pale pink colour, indicating that the endpoint had been reached.

The procedure was repeated for each of the three flasks. Multiple titrations were performed until three consistent results were obtained. Consistency was defined as titration volumes that did not differ from one another by more than 0.1 mL.