Question

The chemical name of nitre is:
a.) Potassium nitrate
b.) Sodium nitrate
c.) Ammonium nitrate
d.) Calcium nitrate

Answer 1

Hint: Nitre is a chemical compound of a group 1 element. The anionic part of nitre is nitrate ion. Another name for nitre is ‘saltpetre’.

Complete step by step answer: Nitre is the mineral form of potassium nitrate. Potassium nitrate is also known as saltpetre or saltpeter. The molecular formula of potassium nitrate (nitre) is \[KN{O_3}\]. It is an ionic salt, where the cation is potassium ion \[{K^ + }\] and the anion is nitrate ion \[N{O_3}^ - \]. It occurs in nature as a mineral, nitre. It is a source of nitrogen, and nitrogen was named after nitre. It is one of the several nitrogen containing compounds, collectively referred to as saltpetre.
Potassium nitrate has an orthorhombic crystal structure at room temperature. It is moderately soluble in water and its solubility increases with temperature. The aqueous solution of potassium nitrate is almost neutral, the pH of which is 6.2 at 14 °C for a 10% solution of commercial powder.
Major uses of potassium nitrate are in fertilizers, tree stump removal, rocket propellants and fireworks. It is also one of the major constituents of gunpowder. In processed meats, potassium nitrate reacts with haemoglobin and generates a pink colour.

Hence, the correct answer is (A) Potassium nitrate.

Note: Do not confuse nitre with soda nitre, which is actually sodium nitrate. It was historically mined in Chile, hence also known as Chile saltpetre.