Salts And Tests

Question 1

Lithium flame colour Li+

Answer 1

Red

Question 2

Sodium flame colour Na+

Answer 2

Yellow

Question 3

Potassium flame colour K+

Answer 3

Lilac

Question 4

Calcium flame colour Ca2+

Answer 4

Orange-red

Question 5

Copper flame colour Ca 2*

Answer 5

Blue-green

Question 6

Barium flame colour

Answer 6

Apple green

Question 7

Positive test for carbonate CO32-

Answer 7

1. Add hydrochloride acid, look for effervescence

2. If there is fizzing bubble gas through limewater to confirm CO2

Question 8

Positive test for Sulfate SO42-

Answer 8

1. Add hydrochloric acid, look for effervescence
2. If there’s no effervescence add barium chloride solution
3. If SO42- ions are present, a white precipitate forms (BaSO4)

Question 9

Test for ammonia

Answer 9

Place damp red litmus paper in a sample of gas, it turns blue

Question 10

Test for Chlorine

Answer 10

Place damp blue litmus paper in a sample of gas, it turns white

Question 11

Soluble

Answer 11

Sodium potassium ammonium
Nitrate
Chloride except silver and lead
Sulphate except silver lead calcium and barium

Question 12

Insoluble

Answer 12

Carbonate Oxide Hydroxide (except calcium)

Except sodium potassium ammonium

Question 13

Acid + Alkali

Answer 13

Salt + water

Question 14

Acid + Base

Answer 14

Salt + Water

Question 15

Acid + Carbonate

Answer 15

Salt + water + carbon dioxide

Question 16

Acid + metal

Answer 16

Salt + hydrogen

Question 17

Is the salt soluble: yes

Does it contain Na+ K+ NH4+: yes

Answer 17

Titration (neutralisation)

Question 18

Is the salt soluble: yes

Does it contain Na+ K+ NH4+: No

Answer 18

Insoluble base + acid (neutralisation)

Question 19

Is the salt soluble: no

Answer 19

Precipitation

Question 20

Precipitation to make an insoluble salt

Answer 20

Mix solutions
Stir
Filter
Rinse with distilled water
Dry with filter paper

Question 21

Insoluble base neutralisation: between acid and insoluble base to make soluble salt

Answer 21

Add base to hot acid
Keep adding solid until the first specs do not disappear
Filter off excess solid, keeping the filtrate (salt solution)

Question 22

Titration (neutralisation between acid and alkali to make soluble salt)

Answer 22

Use a volumetric pipettes to put 25cm alkali into flask
Are a few drops of indicator
Fill burette with acid
Add acid to alkali swirling all the time
Stop when indicator changes colour
Record initial and final burette volumes
Repeat experiment to get concordant results
Repeat again without indicator to run through exact amount

Question 23

Crystallising salts

Answer 23

Heat salt solution to boil off water (makes solution saturated)
Leave solution to cool and evaporate
Filter off and dry crystals with filter paper

Question 24

Test for Cu2+ Fe2+ Fe3+

Answer 24

Dissolve sample in water
Add a few drops NaOH (aq) sodium hydroxide

Copper 2+ blue
Iron 2+ green
Iron 3+ brown