Question

Potassium nitrate is called:
(A) Mohr’s salt
(B) Indian saltpetre
(C) Gypsum
(D) Chile saltpetre

Answer 1

Hint Potassium nitrate is a white coloured, water soluble compound. It has salty taste with a cool and glasslike lustre. It commonly occurs on Earth’s surface, on walls, rocks, and in caves. It is known to form in certain soils in Spain, Italy, Egypt, Iran, and India.

Complete answer:
- Potassium nitrate, $KN{{O}_{3}}$is slightly hygroscopic, which means having a tendency to absorb moisture from the air.
- It is a crystalline compound, produced by nitrification in soil. Potassium nitrate is used in gunpowder, fertilizers, and preservatives.
- The deposits in the great limestone caves of Kentucky, Virginia, and Indiana have probably been derived from the overlying soil and accumulated by penetrating water.
- Potassium nitrate was used at one time in many various diseased conditions, especially asthma. But now it is rarely used medicinally, except as a diuretic. It is assumed to have value as a drug for suppressing sexual desire is purely imaginary.
- Potassium nitrate is commonly known as Indian saltpetre or nitre. It has been used by humans for many centuries.
- It is commercially made by reacting potassium chloride,$KCl$ with nitric acid,$HN{{O}_{3}}$ at high temperatures.
\[3KCl+4HN{{O}_{3}}\to 3KN{{O}_{3}}+C{{l}_{2}}+NOCl+2{{H}_{2}}O\]

The answer to the question is (B) Indian saltpetre.

Note: Under warm climatic conditions, as bacteria decompose animal faeces and other organic matter, it is formed. The appearance of this compound is usually white coloured powder on the surface of soil. Potassium nitrate sources are known to be useful on a small-scale basis without any commercial value.