Tests for Ions

Question 1

Is magnesium sulphate soluble or insoluble?

Answer 1

soluble

Question 2

Is magnesium chromate soluble or insoluble?

Answer 2

soluble

Question 3

Is strontium sulphate soluble or insoluble?

Answer 3

insoluble

Question 4

Is strontium chromate soluble or insoluble?

Answer 4

soluble

Question 5

Is barium sulphate soluble or insoluble?

Answer 5

insoluble

Question 6

Is barium chromate soluble or insoluble?

Answer 6

insoluble

Question 7

Charge on NH4 ion

Answer 7

1+

Question 8

Charge on OH ion

Answer 8

1-

Question 9

Charge on NO3 ion

Answer 9

1-

Question 10

Charge on HCO3 ion

Answer 10

1-

Question 11

Charge on CO3 ion

Answer 11

2-

Question 12

Charge on SO4 ion

Answer 12

2-

Question 13

Charge on PO4 ion

Answer 13

3-

Question 14

Describe the method for testing for group 2 metal ions

Answer 14

• add metal chloride solution to test tube
• add sodium hydroxide solution until in excess and swirl (ammonium solution or sulfuric acid can be used instead)
• observe result

Question 15

Result when magnesium chloride is mixed with ammonium solution

Answer 15

white precipitate
Mg(OH)2

Question 16

Result when magnesium chloride is mixed with excess NaOH

Answer 16

white precipitate
Mg(OH)2

Question 17

Result when magnesium chloride is mixed with excess H2SO4

Answer 17

colourless solution

Question 18

Result when calcium chloride is mixed with ammonium solution

Answer 18

no change

Question 19

Result when calcium chloride is mixed with excess NaOH

Answer 19

white precipitate
Ca(OH)2

Question 20

Result when calcium chloride is mixed with sulfuric acid

Answer 20

slight white precipitate
CaSO4

Question 21

Result when strontium chloride is mixed with ammonium solution

Answer 21

no change

Question 22

Result when strontium chloride is mixed with excess NaOH

Answer 22

slight white precipitate
Sr(OH)2

Question 23

Result when strontium chloride is mixed with excess sulfuric acid

Answer 23

white precipitate
SrSO4

Question 24

Result when barium chloride is mixed with ammonium solution

Answer 24

no change

Question 25

Result when barium chloride is mixed with excess NaOH

Answer 25

no change

Question 26

Result when barium chloride is mixed with sulfuric acid

Answer 26

white precipitate
BaSO4

Question 27

Describe the method for testing for ammonium ions

Answer 27

• 10 drops of solution containing ammonium ions
• 10 drops of NaOH
• swirl to mix
• heat in water bath above bunsen
• place red litmus paper near fumes
• ammonia gas turns it blue (positive result)

Question 28

Describe the method to test for halide ions

Answer 28

• add a small amount of nitric acid to the sample
• add a small amount of silver nitrate to the sample too

Question 29

Describe the result you would see for chlorine ions after silver nitrate test

Answer 29

white precipitate that dissolves in dilute ammonia

Question 30

Describe the result you would see for bromine ions after silver nitrate test

Answer 30

cream precipitate that dissolves in conc ammonia

Question 31

Describe the result you would see for iodine ions after silver nitrate test

Answer 31

yellow precipitate that doesn’t dissolve in any conc of ammonia

Question 32

Describe how you would test for hydroxide ions

Answer 32

• red litmus turns blue
• pH using universal indicator is alkaline

Question 33

Describe the method for testing for carbonate ions

Answer 33

• dilute HCl in test tube
• equal volume of sodium carbonate
• attach a bung with a delivery tube and put the delivery tube into a new test tube containing limewater
• carbonate ions and hydrogen ions react to make carbon dioxide which turns limewater milky

Question 34

Describe how you would test for sulphate ions

Answer 34

• acidify sample with dilute HCl
• add a few drops of aqueous barium chloride
• white precipitate forms if sulphate ions are present