IGCSE Edexcel- Chemistry: Chemical Analysis

Question 1

Oxygen

Answer 1

glowing splint relights

Question 2

Hydrogen

Answer 2

lit splint combusts with a pop

Question 3

Carbon dioxide

Answer 3

bubble through colorless limewater, turns cloudy due to formation of white ppt

Question 4

Chlorine

Answer 4

damp blue litmus paper bleaches white

Question 5

Ammonia

Answer 5

damp red litmus paper turns blue, add HCl white solid

Question 6

Water

Answer 6

anhydrous copper sulfate white to blue, anhydrous cobalt(II) chloride paper blue to pink

Question 7

Hydrogen chloride

Answer 7

damp blue litmus paper turns red, add Ammonia white smoke (solid)

Question 8

Alkenes

Answer 8

bromine water orange to colorless

Question 9

Hydrogen ions

Answer 9

add indicator, reactive metal/carbonate effervesces

Question 10

Li+

Answer 10

Red

Question 11

Na+

Answer 11

Yellow

Question 12

K+

Answer 12

Lilac

Question 13

Ca²+

Answer 13

Orange red, Brick red
add sodium hydroxide dropwise then in excess formation of white ppt

Question 14

Cu²+

Answer 14

Blue green,
add sodium hydroxide dropwise then in excess formation of blue ppt

Question 15

Ba²+

Answer 15

Apple green

Question 16

NH₄+

Answer 16

add sodium hydroxide and heat. no precipitate, smells of ammonia. Ammonia gas released turns damp red litmus blue

Question 17

Fe²+

Answer 17

add sodium hydroxide dropwise then in excess formation of green ppt turns brown on standing

Question 18

Fe³+

Answer 18

add sodium hydroxide dropwise then in excess formation of brown ppt

Question 19

Mg²+

Answer 19

add sodium hydroxide dropwise then in excess formation of white ppt

Question 20

CO₃²-

Answer 20

add acid effervescence milky limewater due to white ppt

Question 21

SO₄²-

Answer 21

add dilute HCl then barium chloride white ppt of BaSO₄ forms

Question 22

Cl-

Answer 22

add dilute HNO₃ then AgNO₃ white ppt

Question 23

Br-

Answer 23

add dilute HNO₃ then AgNO₃ cream ppt

Question 24

I-

Answer 24

add dilute HNO₃ then AgNO₃ pale yellow precipitate

Question 25

OH-

Answer 25

damp red litmus turns blue

Question 26

thermal decomposition of CuCO₃

Answer 26

green to black

Question 27

thermal decomposition of ZnCu₃

Answer 27

white to yellow (white on cooling)

Question 28

Soluble

Answer 28

All Nitrates, sodium, potassium, ammonium, all chlorides except Ba and Pb(II), all sulfates except Ba, Ca, Pb(II)

Question 29

Insoluble

Answer 29

all carbonates and hydroxides except sodium, potassium and ammonium