A student carries out a titration to determine the volume of hydrochloric acid needed to neutralize 25 cm³ of sodium hydroxide. She measured 25 cm³ of sodium hydroxide into a conical flask. Which piece of equipment should she use to do this?
A. Burette B. Measuring cylinder C. Beaker D. Pipette
The Correct Answer and Explanation is :
The correct answer is A. Burette.
Explanation:
In a titration, the goal is to determine the precise volume of one solution required to completely neutralize a known volume of another solution. In this case, the student is aiming to find out how much hydrochloric acid (HCl) is needed to neutralize 25 cm³ of sodium hydroxide (NaOH).
- Burette Usage: A burette is specifically designed for delivering variable volumes of liquid with high precision. It has a tap at the bottom that allows for controlled release of the liquid, which is essential for titration. This control enables the user to add the acid dropwise near the endpoint of the reaction, which is critical for accurately determining the volume needed for neutralization.
- Accuracy and Precision: The burette typically has markings that allow measurements to be read to the nearest 0.01 cm³, providing a high level of accuracy. This is crucial in titration, where slight differences in volume can significantly affect the calculated concentration of the unknown solution.
- Other Equipment Considerations:
- Measuring Cylinder: While a measuring cylinder can measure liquid volumes, it is not designed for the precision needed in titrations. Its graduations are less fine than those on a burette, which could lead to larger errors in determining the endpoint.
- Beaker: A beaker is primarily for mixing solutions rather than precise measurement. It lacks the necessary markings for accurate volume measurement and does not allow controlled dispensing of the titrant.
- Pipette: A pipette is excellent for measuring a specific volume of liquid accurately, but it is not used for dispensing the titrant in a titration. Instead, it is typically used to transfer a fixed volume of one solution (like NaOH) into the flask.
In summary, the burette is the most suitable piece of equipment for delivering hydrochloric acid in a titration due to its precision, control, and design tailored for such experiments.