Tests for cations

Question 1

Describe the test for cation, Aluminium

Answer 1

Effect of adding sodium hydroxide: a white precipitate of aluminium hydroxide that does dissolve in excess to give a colorless solution.
effect of adding aqueous Ammonia: a white precipitate of aluminium hydroxide that does not dissolve in excess

Question 2

Describe the test for cation, Calcium

Answer 2

Effect of adding sodium hydroxide: Forms a white precipitate of Calcium hydroxide that does dissolve in excess.
effect of adding aqueous Ammonia: Does not form a precipitate.In the case that it is formed, it is very slight white precipitate.

Question 3

Describe the test for cation, Chromium

Answer 3

Effect of adding sodium hydroxide: Forms a green precipitate that does dissolve in excess.
effect of adding aqueous Ammonia: Forms a grey-green precipitate that does not dissolve in excess.

Question 4

Describe the test for cation, Copper(II)

Answer 4

Effect of adding sodium hydroxide: Forms a light blue precipitate that does not dissolve in excess.
effect of adding aqueous Ammonia: Forms a light blue precipitate that dissolves in excess to give a dark blue solution.

Question 5

Describe the test for cation, Iron(II)

Answer 5

Effect of adding sodium hydroxide: Forms a green precipitate that does not dissolve in excess.
effect of adding aqueous Ammonia: Forms a green precipitate of Iron(II) hydroxide does not dissolve in water.

Question 6

Describe the test for cation, Iron(III)

Answer 6

Effect of adding sodium hydroxide:Forms a red-brown precipitate of Iron(III) hydroxide that does not dissolve in excess.
effect of adding aqueous Ammonia: Forms a red-brown precipitate that of Iron(III) hydroxide that does not dissolve in excess.

Question 7

Describe the test for cation, Zinc

Answer 7

Effect of adding sodium hydroxide: Forms a white precipitate that does dissolve in excess.
effect of adding aqueous Ammonia: Forms a white precipitate that does dissolve in excess.