Bromine is commercially produced by the oxidation of bromide ions in natural brine with

Options

A. `CI_(2)`
B. `F_(2)`
C. `I_(2)`
D. `O_(2)`

Answer

1

Explanation

Bromine is obtained from sea water and brine lakes. Sea water contains about `65p p m Br^(-)`. Thsu `15` tonnes of sea water contain about `1` kg of bromine. Bromine is extracted from sea water but it is more economical to use more concrntrated brine sources (such as the Dead sea) which contain `2000-5000p p m` of `Br^(-)`. First `H_(2)SO_(4)` is added to adjust the`pH` about `3.5`. Then `Cl_(2)(g)` is passed throught the solution to oxidize the`Br^(-)` to`Br_(2)` (an example of dispacement of one elementby another higher in the electrochemical series):
`Cl_(2)+2Br^(-)rarr2Cl^(-)+Br^(2)`
The `Br_(2)` is removed by a stream of air, because `Br_(2)` is quite volatile. The gas is passed through a solution of `Na_(2)CO_(3)` when the `Br_(2)` is absorbed, forming a mixture of `NaBr` and `NaBrO_(3)` . Finally the solution is acidified and disstilled to giv epure bromine.
`3Br_(2)+3NaCO_(3)rarr5NaBr+NaBrO_(3)+3CO_(2)`
`5NaBr+NaBrO_(3)+3H_(2)SO_(4)rarr5HBr+HBrO_(3)+3Na_(2)SO_(4)`
`5HBr+HBrO_(3)rarr3Br_(2)+3H_(2)O`