Question

A student tests the melting point of a certain sample of potassium alum/tawas. It starts melting at 87-89° C but does not melt completely until the temperature is 91° C. According to a data book, the melting point of potassium alum is 92.5° C. What can you say about the sample?

15. Liquid A is ____
16. Liquid B is ____​

Answer 1

Answer:

I don't know

Explanation:

sorry nerds

Answer 2

(15. Liquid A is ____

16. Liquid B is ____​ part of the above text is not a continuation of the mentioned question).

The sample is impure as it shows deviation from the normal melting point.

• Several tests can be done to gauge the purity of a sample. Melting point test is one of them as a depression or elevation in the boiling point confirms that the mixture is impure.

• The impurities disrupt the molecular arrangements of the compound thereby changing its physical and chemical properties like boiling point, melting point, reactivity etc.

• Thus, according to the question the sample of potash alum starts melting at 87-89° C but does not melt completely until the temperature is 91°C which is lower than the actual lab value confirming impurities in the mixture.