Experiments (flame and ion tests)

Question 1

Ion Test - Ammonium (NH4 +)

Answer 1

1. add dilute sodium hydroxide solution
2. gently heat
3. if NH4 + is present: choking smell produced, fumes turn damp red litmus paper or damp universal indicator from red to blue

Question 2

Ion Test - Carbonate (CO3 2-)

Answer 2

1. add dilute hydrochloric acid
2. bubble gas through limewater
3. if CO3 2- is present, limewater turns cloudy

Question 3

Ion Test - Sulfate (SO4 2-)

Answer 3

1. add dilute hydrochloric acid
2. add a few drops of barium chloride solution
3. if SO4 2- is present, a white precipitate forms

Question 4

Ion Test - Hallide ions
Chloride ions (Cl-)
Bromide ions (Br-)
Iodide ions (I-)

Answer 4

1. add dilute nitric acid
2. then add a few drops of silver nitrate solution
3. if Cl- is present, a white precipitate forms
   if Br- is present, a cream precipitate forms
   if I- is present, a yellow precipitate forms

Question 5

Flame tests

Answer 5

Flame tests are used to detect the presence of a metal ion.
Lithium (Li+) = red flame
Sodium (Na+) = intense yellow/orange flame
Potassium (K+) = purple/lilac/violet flame
Calcium (Ca 2+) = brick red flame