Qualitative Analysis Cations

Question 1

Al3+ (NaOH)

Answer 1

Few drops: white precipitate

Excess: dissolves in excess to form colourless solution

Question 2

Al3+ (NH3)

Answer 2

Few drops: white precipitate

Excess: insoluble in excess

Question 3

Ca2+ (NaOH)

Answer 3

Few drops: white precipitate

Excess: insoluble in excess

Question 4

Ca2+ (NH3)

Answer 4

Few drops: no precipitate

Excess: no precipitate

Question 5

Cu2+ (NaOH)

Answer 5

Few drops: light blue precipitate

Excess: insoluble in excess

Question 6

Cu2+ (NH3)

Answer 6

Few drops: Light blue precipitate

Excess: dissolved to give deep blue solution

Question 7

Fe2+ (NaOH)

Answer 7

Few drops: green precipitate

Excess: insoluble in excess

Question 8

Fe2+ (NH3)

Answer 8

Few drops: green precipitate

Excess: insoluble in excess

Question 9

Fe3+ (NaOH)

Answer 9

Few drops: reddish brown precipitate

Excess: insoluble in excess

Question 10

Pb2+ (NaOH )

Answer 10

Few drops: white precipitate

Excess: dissolves in excess to form colourless solution

Question 11

Fe3+ (NH3)

Answer 11

Few drops: reddish brown precipitate

Excess: insoluble in excess

Question 12

Pb2+ (NaOH)

Answer 12

Few drops: white precipitate

Excess: dissolves to give colourless solution

Question 13

Pb2+ (NH3)

Answer 13

Few drops: white precipitate

Excess: insoluble in excess

Question 14

Zn2+ (NaOH)

Answer 14

Few drops: white precipitate

Excess: dissolves in excess to give colourless solutions

Question 15

Zn2+ (NH3)

Answer 15

Few drops: white precipitate formed

Excess: precipitate dissolves to form colourless solution

Question 16

NH4+

Answer 16

Few drops: no precipitate formed

Excess: ammonia gas in evolved when heating. Ammonia turns moist red litmus paper blue.