Required Practicle 7 Identifying Ions

Question 1

What’s the experiment for

Answer 1

How to use chemical tests to identify ions in unknown compounds

Question 2

Test for carbonate ions

Answer 2

Add dilute hydrochloric acid to the solution and if bubbles are produced then there’s carbonate ions

Collect the gass in limewater. If it turns cloudy the gass is carbon dioxide so contains carbonate ions

Question 3

Test for halide ( halogen) ions

Answer 3

Add dilute nitric acid to remove carbonate ions then add silver nitrate ions

A precipitate will form which will indicate the halide ions present

Chlorine produces white precipitate

Bromine produces a cream coloured precipitate

Iodine produces a yellow precipitate

Question 4

Test for sulphate ions

Answer 4

Acidify the sample with dilute hydrochloric acid to remove carbonate ions then add barium chloride solution

A white precipitate will form I’d sulphate ions present

Question 5

For every flame test

Answer 5

Dip a clean wire loop into a sample then place in a bunsen burner flame

Question 6

Lithium flame

Answer 6

Crimson

Question 7

Sodium flame

Answer 7

Yellow

Question 8

Pottasium

Answer 8

Lilac

Question 9

Calcium

Answer 9

Orange red

Question 10

Copper

Answer 10

Green

Question 11

Colour precipitate formed from aluminium, calcium and magnesium

Answer 11

White

Question 12

What solution is used to test for metal ions which form metal hydroxide which are insoluble and form precipitates

Answer 12

Dilute sodium hydroxide solution

Question 13

What colour does copper 2s precipitate turn

Answer 13

Blue

Question 14

What colour does iron 2 precipitate turn

Answer 14

Green

Question 15

What colour does iron 3 precipitate turn

Answer 15

Brown

Question 16

How to distinguish between aluminium calcium and magnesium ions

Answer 16

Add excess sodium hydroxide solution so

The aluminium white precipitate dissolves to form a colourless solution

The calcium and magnesium white precipitate is unchanged