Question

Caliche is
(A) Impure nitrate
(B) Impure carnallite
(C) Crude saltpeter
(D) Ashes of sea-weeds

Answer 1

Hint: Caliche is commonly known as calcrete. It is called kankar in India. Salitre is a mixture of Sodium nitrate ($NaN{O_3}$) and potassium nitrate ($KN{O_3}$). Salitre is obtained from caliche.

Complete step by step solution:
We will get some information about caliche.
- Caliche is commonly known as calcrete. It is called kankar in india. The original meaning of caliche in Spanish is lime. It is a sedimentary rock.
- In Chile and Peru, actually caliche refers to deposits of minerals that include nitrate salts.
- It is believed that caliche is a mixture of nitrate salts, gypsum, sodium chloride and other salts.
- This caliche also is related to salitre. Salitre is actually saltpeter of Chile. So, salitre is a mixture of Sodium nitrate ($NaN{O_3}$) and potassium nitrate ($KN{O_3}$). In earlier times, it was the most important source of nitrates.
- Potassium nitrate is one of the particular nitrogen compounds that are called saltpeter or saltpetre.
- Caliche contains up to 25% of sodium nitrate and 3% of potassium nitrate.
- The soil which has a significant amount of caliche turns the soil basic in nature and this makes it difficult for the plants to get enough nutrients.
- Carnallite is actually a hydrated potassium magnesium chloride. Thus, it does not have any relation with caliche.

So, we can conclude that the correct answer is (C).

Note: Note that caliche is also referred to as a sedimentary rock that is made up of calcium carbonate mainly. Its colours may range from white to reddish brown depending upon the impurities present. It is used in construction worldwide.