Question

What are hydrous substances? Explain with examples.

Answer 1

Hint: There are two types of inorganic compounds such as hydrous substance and anhydrous substances. This can be classified on the basis of water molecules. The compounds which have water molecules in their structures or molecular formula then they are known as hydrous substances while the compounds which do not contain any water molecules in their structure or chemical formula are known as Anhydrous substances. We will now see hydrous substances in detail.

Complete answer:
We know that inorganic and organic compounds are classified in two types such as hydrous substance and anhydrous substances on the basis of water molecules. So, the compounds which contain water molecules in its structure and chemical formula are referred to as hydrous substances.
In hydrous substances, the water molecules are bonded to the cationic part or metal atom through a chemical bond. These water molecules are known as water of crystallization or the water of hydration.
So, we can say that hydrous substances release water molecules when heated.
Now, we will give some examples of hydrous substances:
Gypsum is a chemical substance which has a chemical formula as $CaS{O_4}.2{H_2}O$ . In this compound, we can see that there are two molecules of water of crystallization.
Plaster of Paris is a derivative of gypsum and has a chemical formula as $CaS{O_4}.\dfrac{1}{2}{H_2}O$ .

Note:
The other type of compounds are anhydrous compounds. These compounds do not contain any water of crystallization or water of hydration in its structure. These types of compounds can be used as drying agents as they can easily accept the water molecules. Silica gel is an example of anhydrous substance.