Question

Bromine is obtained on a commercial scale from
A. Caliche
B. Carnallite
C. Common salt
D. Cryolite

Answer 1

Hint: The bromine can be obtained from the compounds or ores which contain bromine as its constituent element. From the above examples only carnallite is a compound of bromine so, bromine is obtained from carnallite.

Complete Step by Step Answer:
Carnallite is an ore of magnesium and potassium. It contains chlorine atoms. After the crystallisation of potassium chloride from carnallite the liquid remains is called mother liquor. It contains bromine in the form of magnesium bromide and potassium bromide. The bromine can be easily obtained from the salt of magnesium bromide and potassium bromide.

Common salt contains chlorine atoms as it has the chemical formula of $NaCl$ . Thus bromine cannot be obtained from common salt. Caliche is a hard rock that contains calcium carbonate with sand, rocks etc. Thus bromine cannot be obtained from caliche. Cryolite is sodium aluminium fluoride. It is used to obtain fluorine. Thus bromine cannot be obtained from cryolite. Thus Bromine is obtained on a commercial scale from Carnallite.
Thus the correct option is B.

Note: Carnallite is a mineral which is used in fertilisers because it contains potash. It is a soft, white halide mineral that contains hydrated potassium and magnesium chloride. It is generally utilised in composts. It is the most important source of potash.