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Use the data below to sketch (on graph paper) the pH curve for a titration between 20 cm³ of ethanoic acid and a sodium hydroxide solution added from a burette - Leaving Cert Chemistry - Question b - 2003
Question b
Use the data below to sketch (on graph paper) the pH curve for a titration between 20 cm³ of ethanoic acid and a sodium hydroxide solution added from a burette. Vol... show full transcript
Worked Solution & Example Answer:Use the data below to sketch (on graph paper) the pH curve for a titration between 20 cm³ of ethanoic acid and a sodium hydroxide solution added from a burette - Leaving Cert Chemistry - Question b - 2003
Step 1
Sketch the pH Curve
Answer
To sketch the pH curve, plot the points from the provided data on graph paper. The x-axis will represent the volume of NaOH added (cm³), ranging from 0 to 35, while the y-axis will represent the pH values. Ensure that the axes are correctly labeled.
- Plot the points: (0, 3.1), (5, 4.2), (10, 5.6), (15, 6.0), (19, 11.6), (21, 12.1), (25, 12.4), and (30, 12.6).
- Connect the points smoothly to illustrate the curve, showing a significant jump in pH around the equivalence point (around 19 cm³).
Step 2
What indicator would you use for this titration?
Answer
For this titration, the most suitable indicator would be phenolphthalein. The reason for this choice is due to the sharp change in pH at the equivalence point observed on the pH curve. Phenolphthalein changes from colorless to pink between pH 8.2 and 10, making it an ideal choice as it will provide a clear color change right at the endpoint of the titration.