Test for Cations

Question 1

Test for Aluminium (AL3+)

Answer 1

Add NaOH - White precipitate forms
Excess NaOH - White precipitate disappears
Add NH3 - White precipitate forms

Question 2

Test for Ammonium (NH4+)

Answer 2

Add NaOH - No precipitate
Then heat and test gas - Turns red litmus blue

Question 3

Test for Calcium (CA2+)

Answer 3

Add NaOH - White precipitate forms
Excess NaOH - White precipitate remains

Question 4

Test for Copper (CU2+)

Answer 4

Add NaOH - Blue precipitate forms
Add NH3 then in excess - Blue precipitate then dark blue solution

Question 5

Test for Iron (II) (Fe2+)

Answer 5

Add NaOH - Green precipitate forms

Question 6

Test for Iron (III) (Fe3+)

Answer 6

Add NaOH - Brown precipitate forms

Question 7

Test for Zinc (ZN2+)

Answer 7

Add NaOH - White precipitate forms
Excess NaOH - White precipitate disappeared
Add NH3 then excess- White precipitate forms then disappears