Question 39

Accurate volumetric measurement of a solution in a graduated cylinder is indicated by the bottom of the meniscus.

Accurate volumetric measurement in a graduated cylinder is determined by observing the bottom of the meniscus, which is the curve formed by the liquid's surface. This point provides the most reliable indication of the liquid's volume.

A) Top of the meniscus

Measuring at the top of the meniscus is incorrect because it does not provide an accurate representation of the liquid volume. The top of the meniscus is influenced by surface tension and can lead to overestimation of the volume.

B) Error of parallax

While the error of parallax can affect measurements, it is not an indication of where to read the volume. Instead, parallax refers to the visual misjudgment that can occur if the observer's eye is not level with the meniscus, leading to inaccurate readings regardless of the chosen measurement point.

C) Surface tension force

Surface tension force affects how the liquid curves in the cylinder but does not dictate the correct measurement point. It is the reason for the meniscus's shape rather than a factor in determining where to read the volume.

D) Bottom of the meniscus

The bottom of the meniscus is the correct measurement point because it allows for the most accurate reading of the liquid level in the graduated cylinder. This point minimizes the effects of surface tension and provides a consistent reference for measurement.

Conclusion

The bottom of the meniscus is definitively the correct choice for accurate volumetric measurement in a graduated cylinder, as it reflects the true liquid level. In contrast, the other options either misrepresent where to measure or highlight factors that complicate accurate readings. Understanding the meniscus and its implications is essential for precision in laboratory measurements.