Question

Which of the following does not contain nitrogen?
A.Proteins in plants and animals
B.Members of apatite family
C.Indian saltpetre
D.Chile saltpetre

Answer 1

Nitrogen is one of the most abundant elements in the universe. It is the fifth most abundant element on earth and it forms about $78\%$ of the earth’s atmosphere. To solve this question, we must first discuss the chemical composition of the options given to us. Nitrogen is usually present in all biological life forms.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Nitrogen serves an important purpose in both plant and animal biology. Hence, most of the living beings have some or the other form of nitrogen present in them. Let us now discuss the options:
1.Proteins in plants and animals:
Proteins in plants and animals are usually formed from compounds known as amino acids. Amino acids contain one carboxylic group and one amine group. The carboxylic group is responsible for giving the acidic characteristics to the compound, as well as it serves as a site for linking with other compounds. On the other hand, the amine group acts as the basic end of the compound and inherits basic characteristics to the compound. Hence, proteins of any form contain nitrogen.
2.Members of apatite family:
The apatite family can be understood as a group of phosphate minerals. These minerals have huge abundances of chemical substituents like hydroxyl ion, fluoride ion and chloride ion.
3.Indian saltpetre: Indian Saltpetre is one of the key ingredients in the gunpowder. The chemical name of this compound is potassium nitrate. Hence, this compound contains nitrogen.
4.Chile saltpetre: Chile saltpetre is basically an alkali metal nitrate salt. The most commonly used alkali metal is sodium and the corresponding mineral is nitrating. Since the compound contains the nitrate ion, it contains nitrogen.

Hence, Option B is the correct option

Note: The primary use of apatite is in the manufacture of fertilizer – it is a source of phosphorus. It is occasionally used as a gemstone. Green and blue varieties, in finely divided form, are pigments with excellent covering power.