Acid-Base Titrations Quiz

1. Which piece of apparatus is used to add a variable, measured volume of solution during a titration?

• A. Volumetric pipette
• B. Burette
• C. Measuring cylinder
• D. Gas syringe

2. What is the purpose of a volumetric pipette in a titration?

• A. To add a variable volume of solution slowly
• B. To measure out one fixed, precise volume of solution
• C. To heat the solution before titrating
• D. To measure temperature changes during the reaction

3. How is the end-point of a titration identified?

• A. By a sudden increase in temperature
• B. By the colour change of an indicator
• C. By the formation of a gas
• D. By a change in mass of the flask

4. Why is a burette generally preferred over a measuring cylinder for adding the second solution in a titration?

• A. A burette is cheaper to buy
• B. A burette allows a more precise, controllable volume to be added and measured
• C. A burette does not require any liquid to be added slowly
• D. A burette can hold a larger volume of liquid

5. A student titrates 25.0 cm3 of sodium hydroxide solution (measured with a pipette) against hydrochloric acid added from a burette, using phenolphthalein indicator. Explain how the student would know when to stop adding acid, and why the pipette and burette are each suited to their specific roles in this experiment.

• A. The student stops when the solution starts bubbling; the pipette and burette are interchangeable in this experiment
• B. The student stops when the phenolphthalein changes from pink to colourless (the end-point); the pipette measures the fixed, precise volume of alkali while the burette allows the variable volume of acid to be added and measured accurately
• C. The student stops after exactly 5 minutes regardless of colour; apparatus choice does not affect the result
• D. The student stops when the flask reaches a fixed temperature; the burette measures temperature while the pipette measures volume