Tests for Aqueous Cations

Question 1

Aqueous sodium hydroxide + aluminium (Al³+)

Answer 1

White ppt., soluble in excess, giving a colourless solution

Question 2

Aqueous sodium hydroxide + ammonium (NH4 +)

Answer 2

Ammonia produced on warming

Question 3

Aqueous sodium hydroxide + calcium (Ca²+)

Answer 3

White ppt., insoluble in excess

Question 4

Aqueous sodium hydroxide + chromium (III) (Cr³+)

Answer 4

Green ppt., soluble in excess

Question 5

Aqueous sodium hydroxide + copper (II) (Cu²+)

Answer 5

light blue ppt., insoluble in excess

Question 6

Aqueous sodium hydroxide + iron(II) (Fe²+)

Answer 6

green ppt., insoluble in excess

Question 7

Aqueous sodium hydroxide + iron (III) (Fe³+)

Answer 7

red-brown ppt., insoluble in excess

Question 8

Aqueous sodium hydroxide + zinc (Zn²+)

Answer 8

White ppt., soluble in excess, giving a colourless solution

Question 9

Ammonia solution + aluminium (III) ions

Answer 9

White precipitate forms, insoluble in excess

Question 10

Ammonia solution + zinc ions

Answer 10

White precipitate forms, soluble in excess