Qualitative Analysis

Question 1

Cu2+
1. Solution Colour
2. Addition of NaOH (aq)
3. Addition of NH3 (aq)

Answer 1

1. Blue
2. Light blue ppt, insoluble in excess NaOH
3. Light blue ppt, soluble in excess NH3 to give dark blue solution

Question 2

Fe2+
1. Solution Colour
2. Addition of NaOH (aq)
3. Addition of NH3 (aq)

Answer 2

1. Green
2. Green ppt formed, insoluble in excess
3. Green ppt formed, insoluble in excess

Question 3

Fe3+
1. Solution Colour
2. Addition of NaOH (aq)
3. Addition of NH3 (aq)

Answer 3

1. Yellow
2. Reddish-brown ppt formed, insoluble in excess
3. Reddish-brown ppt formed, insoluble in excess

Question 4

Zn2+
1. Solution Colour
2. Addition of NaOH (aq)
3. Addition of NH3 (aq)

Answer 4

1. Colourless
2. White ppt formed, soluble in excess giving colourless solution
3. White ppt formed, soluble in excess giving colourless solution

Question 5

Al3+
1. Solution Colour
2. Addition of NaOH (aq)
3. Addition of NH3 (aq)

Answer 5

1. Colourless
2. White ppt formed, soluble in excess giving colourless solution
3. White ppt formed, insoluble in excess

Question 6

Ca2+
1. Solution Colour
2. Addition of NaOH (aq)
3. Addition of NH3 (aq)

Answer 6

1. Colourless
2. White ppt formed, insoluble in excess
3. No ppt

Question 7

NH4+
1. Solution Colour
2. Addition of NaOH (aq)
3. Addition of NH3 (aq)

Answer 7

1. Colourless
2. Ammonia produced upon warming, turns red litmus paper blue

Question 8

Carbonate Ion/CO3^2-

Answer 8

Add any dilute acid

Bubble gas produced into limewater