Testing for Halides

Question 1

Halide ions can be identified in an unknown solution by dissolving the solution in ……………………………………….acid

and then adding…………..

Answer 1

nitric acid and then adding silver nitrate solution dropwise

Question 2

The nitric acid is to

Answer 2

prevent any false positive results from carbonate ions precipitating out with silver ions

Question 3

The halide ions will react with the silver nitrate solution as follows

Answer 3

Ag+ (aq) + X- (aq) → AgX (s)

ionic equation)

Question 4

Where X- is the halide ion
The state symbols are key in this equation
If the unknown solution contains halide ions, a precipitate of the ……. will be formed (AgX)

Answer 4

silver halide

Ag+ (aq) + X- (aq) → AgX (s)

Question 5

Silver chloride (AgCl) is a …..precipitate

Silver bromide (AgBr) is a…………precipitate.

Silver iodide (AgI) is a ………………precipitate

Answer 5

Silver chloride (AgCl) is a white precipitate
Silver bromide (AgBr) is a cream precipitate
Silver iodide (AgI) is a yellow precipitate

Question 6

Because the white, cream and yellow precipitates could look very similar in colour, ………………. is often used as a follow up test to determine which halide ion is present

Answer 6

ammonia

Question 7

..followed by …………………………..ammonia is added to the silver halide solution to identify the halide ion

Answer 7

Dilute

concentrated

Question 8

If the precipitate dissolves in dilute ammonia the unknown halide is

Answer 8

chloride

Question 9

If the precipitate does not dissolve in dilute, but does dissolve in concentrated ammonia the unknown halide is

Answer 9

bromide

Question 10

If the precipitate does not dissolve in dilute or concentrated ammonia, then the unknown halide is

Answer 10

iodide