qualitative analysis - tests

what are the anions that can be tested?

1. carbonate (CO3 -)

2. chloride (CI -)

3. iodide (I -)

4. nitrate (NO3 -)

5. sulfate (SO4 2-)

test for carbonate (CO3 2-)

test: add dilute acid

result: effervescence is formed, carbon dioxide produced

test for chloride (CI - )

test: acidify with dilute nitric acid, then add aqueous silver nitrate

result: white ppt

test for iodide (I -)

test: acidify with dilute nitric acid, then add aqueous silver nitrate

result: yellow ppt

test for nitrate (NO3 -)

test: add aqueous sodium hydroxide, then aluminium foil, warm carefully

result: ammonia produced

test for sulfate (SO4 2-)

test: acidify with dilute nitric acid, then add aqueous barium nitrate

result: white ppt

what are aqueous cations that can be tested?

1. aluminium (Al3+)

2. ammonium (NH4+)

3. calcium (Ca2+)

4. copper (II) (Cu2+)

5. iron (II) (Fe2+)

6. iron (III) (fe3+)

7. zinc (Zn2+)

test for aluminium (Al3+)

effect of aqueous sodium hydroxide: white ppt, soluble in excess giving a colorless solution

effect of aqueous ammonia: white ppt, insoluble in excess

test for ammonium (NH4+)

effect of aqueous sodium hydroxide: ammonia produced after warming

effect of aqueous ammonia: NIL

test for calcium (Ca2+)

effect of aqueous sodium hydroxide: white ppt, insoluble in excess

effect of aqueous ammonia: no ppt

test for copper (II) (Cu2+)

test for aqueous sodium hydroxide: light blue ppt, insoluble in excess

test for aqueous ammonia: light blue ppt, soluble in excess, giving a dark blue solution

test for iron (II) (Fe2+)

test for aqueous sodium hydroxide: green ppt, insoluble in excess

test for aqueous ammonia: green ppt, insoluble in excess

test for iron (III) (Fe3+)

test for aqueous sodium hydroxide: reddish-brown ppt, insoluble in excess

test for aqueous ammonia: reddish-brown ppt, insoluble in excess

test for zinc (Zn2+)

test for aqueous sodium hydroxide: white ppt, soluble in excess, giving a colorless solution

test for aqueous ammonia: white ppt, soluble in excess, giving a colorless solution

what are the gases that can be tested?

1. ammonia (NH3)

2. carbon dioxide (CO2)

3. chlorine (CI2)

4. hydrogen (H2)

5. oxygen (O2)

6. sulfur dioxide (SO2)

test for carbon dioxide (CO2)

gives white ppt with limewater (ppt dissolves in excess limewater)

test for chlorine (Cl2)

bleaches damp lithmus paper

test for hydrogen (H2)

gives a ‘pop’ sound when come into contact with lighted split

test for oxygen (O2)

relights a glowing splint

test for sulfur dioxide (SO2)

turns aqueous acidified potassium maganate (VII) from purple to colorless