how do u extract halogens?

Answer 1

This is different for the different halogens. Chlorine is obtained by electrolysis of sea-water, but bromine and iodine can be obtained by using the differences in reactivity between them and chlorine. Look them up as "extraction of chlorine" and "extraction of bromine" (and so on) and you'll get the answers.

Answer 2

In the laboratory halogens can be extracted by oxidising each halide. Chlorine is made by adding concentrated hydrochloric acid to manganese dioxide, the gas is passed through water to remove hydrogen chloride and then concentrated sulphuric acid to remove water vapour. In industry it is made by the electrolysis of sodium chloride solution.
Bromine can be made by heating a mixture of concentrated sulphuric acid, potassium bromide and manganese dioxide in a retort and condensing the vapour in a flask cooled with water. Bromine can also be made by passing chlorine into potassium bromide solution. In industry bromine is made by passing chlorine into sea water and 'blowing out' the bromine with air.
Iodine can be made in the same way as bromine but using potassium iodide instead of the bromide.
Fluorine has to be made by the electrolysis of a molten mixture of hydrogen fluoride and potassium fluoride (this is not at a high temperature as the potassium fluoride dissolves in the liquid hydrogen fluoride which is at below 19C.)

Answer 3

By Electrolysis

Answer 4

carefully