How do you determine if a compound is a halide?

2 Answers
Aug 6, 2016

A halide is a salt with a an element from the Halide or group 7A


Group 7A the halides are Florine, Chlorine, Bromine, Iodine. Any compound that has one of these elements as its negative ion will be a halide.

Aug 26, 2016

The determination depends on whether the compound is a halide salt or an organic halogen compound.


Halide salts

Acidify an aqueous solution of the salt with dilute nitric acid.

Then add aqueous silver nitrate.

You get an immediate precipitate of the silver halide.

#"Ag"^_("aq") + "X"^"-"("aq") → "AgX(s)"; "X = Cl, Br, I"#

Organic Halides

If the compound is an organic halide, we have to convert the covalently bound halogen atoms into their ions.

One way is to use the sodium fusion test.

The sample is heated strongly with clean sodium metal.

#"Na"color(white)(l) + "C,H,X" → "Na"^+ + "X"^"-"#

The "fused" sample is plunged into water.

Then you acidify the solution with nitric acid and test as before with aqueous silver nitrate.