Tests For Ions And Gases COPY

Question 1

Sodium flame

Answer 1

Orange

Question 2

Potassium flame

Answer 2

Lilac

Question 3

Calcium flame

Answer 3

Brick red

Question 4

Testing for ammonia NH4+

Answer 4

Warm with sodium hydroxide solution. Damp with red litmus. Result - litmus paper turns blue, pungent smelling gas

Question 5

What do you use for precipitation tests with copper, iron fe2+ and fe3+

Answer 5

Sodium hydroxide

Question 6

Colour of copper precipitate

Answer 6

Blue

Question 7

Colour of iron fe2+ precipitate

Answer 7

Green

Question 8

Colour of iron fe3+ precipitate

Answer 8

Brown

Question 9

What do you use for precipitation tests with chlorine, bromine and iodine

Answer 9

Dilute nitric acid and silver nitrate solution

Question 10

Colour of chlorine precipitate

Answer 10

White

Question 11

Colour of bromine precipitate

Answer 11

Cream

Question 12

Colour of iodine precipitate

Answer 12

Yellow

Question 13

Test for sulphate SO4 2-

Answer 13

Use dilute hydrochloride acid and barium chloride solution. Positive result : White precipitate

Question 14

Test for carbonate CO3 2-

Answer 14

Using dilute hydrochloric acid. Bubble it through limewater. Positive result : limewater turns cloudy

Question 15

Test for oxygen gas

Answer 15

Put a glowing splint into the gas. Splint should relight

Question 16

Test for carbon dioxide

Answer 16

A lighted wooden splint goes out in a test tube of carbon dioxide but this happens with other gases, too. It is better to bubble the test gas through lime water (calcium hydroxide solution) . Carbon dioxide turns limewater cloudy white

Question 17

Test for ammonia

Answer 17

Ammonia had a characteristic sharp, choking smell. It also makes damp red litmus paper turn blue. Ammonia forms a white smoke of ammonium chloride when hydrogen chloride gas, from concentrated hydrochloric acid, is held near it

Question 18

Test for chlorine

Answer 18

Chlorine has a characteristic shark, choking smell. It also makes damp blue litmus paper turn red, and then bleaches it white. Chlorine makes damp starch - iodide paper turn blue black

Question 19

Lithium flame

Answer 19

Red

Question 20

Test for hydrogen

Answer 20

Put a lit splint into the gas Hydrogen burns with a ‘squeaky pop’ sound