Chemical Tests

Question 1

Ammonia

Answer 1

Red litmus paper turns blue

Question 2

Carbon dioxide

Answer 2

Limewater turns milky

Question 3

Hydrogen

Answer 3

Gas burns with a squeaky pop

Question 4

Oxygen

Answer 4

Glowing Splint relights

Question 5

Ammonium

Answer 5

Heat with NaOH

Red litmus turns blue

Question 6

Mg2+

Answer 6

Flame test- no colour
Add NaOH- white ppt (insoluble in excess)
Add ammonia- white ppt (insoluble in excess)
Add NaCO3- white ppt

Question 7

Ca2+

Answer 7

Flame test- brick red flame
Add NaOH- white ppt (insoluble in excess)
Add ammonia- no reaction
Add NaCO3- white ppt

Question 8

Cu2+

Answer 8

Flame test- blue green flame

Add NaOH- white ppt (insoluble in excess)

Question 9

Fe2+

Answer 9

Add NaOH- dark green ppt

Question 10

Fe3+

Answer 10

Add NaOH- brown ppt

Question 11

K+

Answer 11

Flame test- lilac flame

Question 12

Na+

Answer 12

Flame test- yellow-orange flame

Question 13

Zn2+

Answer 13

Add NaOH- white ppt ( soluble in excess)

Add Ammonia- white ppt (soluble in excess)

Question 14

Al3+

Answer 14

Add NaOH- white ppt (soluble in excess)

Question 15

Cr3+

Answer 15

Add NaOH- grey green ppt (soluble in excess to give dark green solution)

Question 16

Pb2+

Answer 16

NaOH- white ppt (soluble in excess
Insoluble in excess ammonia
Add KI- yellow ppt

Question 17

Ba2+

Answer 17

Flame- apple green
NaOH- no ppt
Add NaCO3- white ppt

Question 18

Br-

Answer 18

Add NO2 and AGNO3- cream ppt

Question 19

Co32-

Answer 19

Add acid- fizz

Question 20

Cl-

Answer 20

Add NO2 and AgNO3- white ppt

Question 21

I-

Answer 21

Add NO2 and AgNO3- yellow ppt

Question 22

SO42-

Answer 22

Add BaCl2- white ppt

Question 23

Aldehyde

Answer 23

Fehilings- brick red sol
Tollens- silver mirror
Triidomethane- yellow ppt (only ethanol)
2,4 DNP- orange ppt

Question 24

Ketone

Answer 24

Triidomethane- yellow ppt

2,4 DNP- orange ppt

Question 25

Carboxylic acid

Answer 25

Na2CO3- fizzing