Why are alum rystals not supposed to washed in pure water?
Because they are soluble in water.
Alum crystals should not be washed in pure water because they are highly soluble in water and will dissolve quickly. Alum is a type of salt known as hydrated potassium aluminum sulfate, which has a chemical formula of KAl(SO4)2·12H2O. When alum crystals come into contact with water, the water molecules break apart the crystal lattice structure and surround the individual ions, causing the crystal to dissolve. Therefore, washing alum crystals in pure water will result in their dissolution, and you will lose the crystal form.
Alum crystals are not supposed to be washed in pure water because they are hygroscopic, which means that they readily absorb moisture from the surrounding environment. Washing alum crystals with pure water would remove any impurities or substances that may be present on the crystals' surface, making them more susceptible to moisture absorption.
To explain how to get the answer to your question, we can start by conducting some research. Firstly, we can search online for information about the properties of alum crystals and their behavior when exposed to water. Reliable sources such as scientific journals, educational websites, or chemistry textbooks can provide the necessary information.
Alternatively, we can consult chemistry experts or perform experiments to confirm the claim that alum crystals should not be washed in pure water. Conducting an experiment would involve obtaining alum crystals and dividing them into two groups. One group could be washed with pure water, while the other is left untouched. We can observe any changes in the crystal's appearance, texture, or weight to analyze the effects of washing with pure water.
By combining research and experimental findings, we can conclude that alum crystals should not be washed in pure water due to their hygroscopic nature.