QA memorise

Question 1

test for ammonia

Answer 1

turns damp red litmus paper blue.
gas evolved is colourless and pungent.

Question 2

test for co2

Answer 2

bubble gas in limewater, co2 will form white ppt.

(dissolves in excess limewater to form colourless solution)

Question 3

test for hydrogen

Answer 3

extinguishes a lighted split with ‘pop’ spund

Question 4

test for oxygen

Answer 4

relights a glowing splint.

Question 5

test for chlorine

Answer 5

turns damp blue litmus paper red, then bleaches it.
gas evolved is yellowish-green and pungent.

Question 6

test for sulfur dioxide

Answer 6

turns acidified potassium manganate (VII) from purple to colourless.
gas evolved is colourless and pungent.

Question 7

test for water vapour

Answer 7

turns dry cobalt (II) chloride paper from blue to pink.
gas evolved is colourless and odourless.

Question 8

use what to test for cations?

Answer 8

aqueous sodium hydroxide and aqueous ammonia

Question 9

observations when ammonium is tested for cations?

Answer 9

ammonia is produced on warming (naoh)

Question 10

observations when calcium is tested for cations?

Answer 10

white ppt (naoh, insoluble in excess)
no ppt (nh3)

Question 11

observations when copper (II) is tested for cations? *

Answer 11

light blue ppt, insoluble in excess (naoh)
light blue ppt, soluble in excess and turns into a dark blue solution
(nh3)

Question 12

observations when iron (II) is tested for cations? *

Answer 12

green ppt, insoluble in excess
(naoh & nh3)

Question 13

observations when iron (III) is tested for cations?

Answer 13

reddish-brown ppt, insoluble in excess
(naoh & nh3)

Question 14

observations when lead (II) is tested for cations?

Answer 14

white ppt, soluble in excess turning into a colourless solution
(naoh)
white ppt, insoluble in excess
(nh3)

Question 15

observations when zinc is tested for cations?

Answer 15

white ppt, soluble in excess turning into a colourless solution
(naoh & nh3)

Question 16

describe test for chloride ions

Answer 16

add dilute nitric acid, then silver nitrate (AgNO3).
white ppt of silver chloride is formed.

Question 17

describe test for iodide ions

Answer 17

add dilute nitric acid, then silver nitrate (AgNO3).
yellow ppt of silver iodide is formed.

Question 18

describe test for sulfate ions

Answer 18

add dilute nitric acid, then barium chloride/nitrate.
white ppt of barium sulfate is formed.

Question 19

describe test for carbonate ions

Answer 19

add dilute hydrochloric acid and effervescence is produced.
carbonate reacts with acid to produce salt, h2o, co2.
test for co2: limewater

Question 20

describe test for nitrate ions

Answer 20

add dilute sodium hydroxide, then a piece of aluminium foil. warm mixture and test for gas evolved.
test for ammonia: litmus paper red > blue

Question 21

how to differentiate between lead (II) and aluminium?

Answer 21

add aqueous potassium iodide.
yellow ppt > lead (II) iodide