Testing for aq halide ions

Question 1

How do we test for aq halide ions?

Answer 1

= silver nitrate is added to a solution containing halide ions
= silver halide precipitate forms- these have different colours
= silver halide precipitates have different solubilities in ammonia

Question 2

What do we add first?

Answer 2

= dilute nitric acid
= removes any carbonate ions

Question 3

What happens to chlorine ions when reacting with silver nitrate and what is its solubility in ammonia?

Answer 3

= forms Agcl solid
= white precipitate
= soluable in dilute ammonia- dissolves
Agcl + Nh3 ==> Ag(Nh3)2+ + Cl^-

Question 4

What happens to bromine ions when reacting with silver nitrate and what is its solubility in ammonia?

Answer 4

= forms Agbr- solid
= cream precipitate
= partially soluable in dilute ammonia, fully soluable in concentrated
Agbr + Nh3 ==> Ag(Nh3)2+ + Br^-

Question 5

What happens to iodide ions when reacting with silver nitrate and what is its solubility in ammonia?

Answer 5

= Agi solid formed
= yellow precipitate
= insoluable in both dilute and concentrated

Question 6

What problem is there by using silver nitrate?

Answer 6

= forms a precipitate with co3^2- ions and sulfate ions
= we need to test for carbonate and sulfate ions first to remove any impurities