Final answer:
Using a burette reading card for colorless solutions in a titration is a helpful but not mandatory practice to enhance the visibility of the meniscus, enabling more precise volume measurements.
Step-by-step explanation:
The statement 'For colorless solutions you must use a burette reading card' is not universally true or false. While a buret reading card, which is typically a piece of card with a contrasting color (often black or other dark color), can be helpful to make the meniscus in a burette more visible against a colorless solution, it is not an absolute requirement. However, using such a card can make it substantially easier to read the correct volume, especially when measuring precise volumes as required in titrations. Therefore, it can be considered a preferred practice rather than a strict requirement.
In a typical titration procedure, a burette is utilized to accurately measure the volume of a liquid, typically a base, that is added to another liquid, usually an acid. The acid-base reaction is monitored by an indicator which changes color at the equivalence point. The exact volume of the liquid dispensed from the burette at the point of color change is crucial to determine the concentration of the unknown solution. This process can be made more accurate with the use of the reading card for colorless solutions, which emphasizes the curve of the meniscus and makes it easier to make precise readings.