Precipitate Test

Question 1

Precipitate Test

Answer 1

When metal ions combine with the hydroxide ions from either sodium or hydroxide solution or ammonia solution, they form insoluble precipitates with characteristic colours

Question 2

Method

Answer 2

-Dissolve small quality of substance in water
-Place about 5cm3 of solution into test tube
-Add few drops of sodium hydroxide solution
-Record colour of any precipitation formed
-Add dilute hydroxide solution until in excess and record the result

Question 3

Copper (II), Cu2+

Answer 3

Adding Solution - Blue precipitate
Adding excess - Blue precipitate remains

Question 4

Iron (II), Fe2+

Answer 4

Adding Solution - Green precipitate
Adding excess - Green precipitate remains

Question 5

Iron (III), Fe3+

Answer 5

Adding Solution - Brown precipitate
Adding excess - red-brown precipitate remains

Question 6

Magnesium, Mg2+

Answer 6

Adding Solution - White precipitate
Adding excess - White precipitate remains

Question 7

Aluminium, Al3+

Answer 7

Adding Solution - White precipitate
Adding excess - Dissolved and colourless solution forms

Question 8

Zinc, Zn2+

Answer 8

Adding Solution - White precipitate
Adding excess - Dissolves and a colourless solution forms