CATIONS AND ANIONS

Question 1

test for carbonate (CO3^2-)

Answer 1

add dilute acid

Question 2

result for carbonate (CO3^2-)

Answer 2

effervescence, carbon dioxide produced

Question 3

test for chloride (Cl^-) [in solution]

Answer 3

• acidify with dilute nitric acid

- add aqueous silver nitrate

Question 4

result for chloride (Cl^-) [in solution]

Answer 4

white ppt

Question 5

test for bromide (Br^-) [in solution]

Answer 5

• acidify with dilute nitric acid

- add aqueous silver nitrate

Question 6

result for bromide (Br^-) [in solution]

Answer 6

cream ppt

Question 7

test for iodide (I^-) [in solution]

Answer 7

• acidify with dilute nitric acid

- add aqueous silver nitrate

Question 8

result for iodide (I^-) [in solution]

Answer 8

yellow ppt

Question 9

test for nitrate (NO3^-) [in solution]

Answer 9

• add aqueous sodium hydroxide
• add aluminium foil
• warm carefully

Question 10

result for nitrate (NO3^-) [in solution]

Answer 10

ammonia produced

Question 11

test for sulfate (SO4^2-) [in solution]

Answer 11

• acidify

- add aqueous barium nitrate

Question 12

result for sulfate (SO4^2-) [in solution]

Answer 12

white ppt

Question 13

test for sulfite (SO3^2-) [in solution]

Answer 13

• add dilute hydrochloric acid
• warm gently
• test for presence of sulfur dioxide

Question 14

result for sulfite (SO3^2-) [in solution]

Answer 14

sulfur dioxide produced will turn acidified aqueous potassium manganate (VII) from purple to colourless

Question 15

aluminium (Al^3+) + aqueous sodium hydroxide effect

Answer 15

• white ppt

- soluble in excess (giving colourless solution)

Question 16

ammonium (NH4^+) + aqueous sodium hydroxide effect

Answer 16

ammonia produced on warming

Question 17

calcium (Ca^2+) + aqueous sodium hydroxide effect

Answer 17

• white ppt

- insoluble in excess

Question 18

chromium (III) (Cr^3+) + aqueous sodium hydroxide effect

Answer 18

• green ppt

- insoluble in excess

Question 19

copper(II) (Cu^2+) + aqueous sodium hydroxide effect

Answer 19

• light blue ppt

- insoluble in excess

Question 20

iron(II) (Fe^2+) + aqueous sodium hydroxide effect

Answer 20

• green ppt

- insoluble in excess

Question 21

iron(III) (Fe^3+) + aqueous sodium hydroxide effect

Answer 21

• red-brown ppt

- soluble in excess giving a colourless solution

Question 22

zinc (Zn^2+) + aqueous sodium hydroxide effect

Answer 22

• white ppt

- soluble in excess, giving a colourless solution

Question 23

aluminium (Al^3+) + aqueous ammonia effect

Answer 23

• white ppt

- insoluble in excess

Question 24

ammonium (NH4^+) + aqueous ammonia effect

Answer 24

-

Question 25

calcium (Ca^2+) + aqueous ammonia effect

Answer 25

• no ppt

- very slight white ppt

Question 26

chromium (III) (Cr^3+) + aqueous ammonia effect

Answer 26

• grey-green ppt

- insoluble in excess

Question 27

copper(II) (Cu^2+) + aqueous ammonia effect

Answer 27

• light blue ppt

- soluble in excess giving a dark blue solution

Question 28

iron(II) (Fe^2+) + aqueous ammonia effect

Answer 28

• green ppt

- insoluble in excess

Question 29

(flame test) lithium ( Li+)

Answer 29

red

Question 30

(flame test) sodium (Na+)

Answer 30

yellow

Question 31

(flame test) potassium (K+)

Answer 31

lilac

Question 32

(flame test) calcium (Ca2+)

Answer 32

orange

Question 33

(flame test) barium (Ba2+)

Answer 33

green

Question 34

(flame test) copper (Ba2+)

Answer 34

blue-green

Question 35

test for ammonia (NH3)

Answer 35

turns damp red litmus paper blue

Question 36

test for carbon dioxide (CO2)

Answer 36

turns limewater milky

Question 37

test for chlorine (Cl2)

Answer 37

bleaches damp litmus paper

Question 38

test for hydrogen (H2)

Answer 38

‘pops’ with a lighted splint

Question 39

test for oxygen (O2)

Answer 39

relights a glowing splint

Question 40

test for sulfur dioxide (SO2)

Answer 40

turns acidified aqueous potassium manganate (VII) from purple to colourless