tests

Question 1

test for carbon dioxide

Answer 1

turns limewater milky

Question 2

test for oxygen

Answer 2

relights glowing splint

Question 3

test for hydrogen

Answer 3

pops a lighted splint

Question 4

test for ammonia

Answer 4

turns dap red litmus paper blue

Question 5

test for sulfur dioxide

Answer 5

turns acidified aqueous potassium magnate from purple to colourless

Question 6

test for hydrochloric acid

Answer 6

turns blue litmus paper red

Question 7

test for chlorine gas

Answer 7

damp blue litmus paper turns red then bleaches

Question 8

NaOH or ammonia method for test for cations

Answer 8

Metal cations in aqueous solution can be identified by the colour of the precipitate they form on addition of sodium hydroxide and ammonia
If only a small amount of NaOH is used then normally the metal hydroxide precipitates
In excess NaOH some of the precipitates may dissolve
A few drops of NaOH is added at first and any colour changes or precipitates formed are noted
Then the NaOH is added in excess and the reaction is observed again
The steps are repeated for the test using ammonia solution

Question 9

results for test for cations

Answer 9

see table https://docs.google.com/document/d/1FEuoHGrHnAgaCxSHhz8YD89lbgVijgTnlItPZ4HTruU/edit

Question 10

Lithium cation flame test

Answer 10

red flame

Question 11

Sodium cation flame test

Answer 11

yellow flame

Question 12

potassium cation flame test

Answer 12

lilac flame

Question 13

Calcium (2+) cation flame test

Answer 13

orange-red flame

Question 14

Copper (2+) flame test

Answer 14

blue-green flame

Question 15

test for carbonate anion

Answer 15

• add dilute acid

- test the released gas

Question 16

result for carbonate anion

Answer 16

effervescence, gas produced is CO2 which turns limewater milky

Question 17

test for chloride anion

Answer 17

acidify with dilute nitric acid and add aqueous silver nitrate

Question 18

result for chloride anion

Answer 18

white ppt

Question 19

test for bromide anion

Answer 19

acidify with dilute nitric acid and add aqueous silver nitrate

Question 20

result for bromide anion

Answer 20

cream ppt

Question 21

test for iodide anion

Answer 21

acidify with dilute nitric acid and add aqueous silver nitrate

Question 22

result for iodide anion

Answer 22

yellow ppt

Question 23

test for nitrate anion

Answer 23

add aqueous NaOH and aluminium foil, warm gently and test the gas released

Question 24

result for nitrate anion

Answer 24

gas given off is ammonia, has a pungent smell and turns moist red litmus paper blue

Question 25

test for sulfate anion

Answer 25

acidify with dilute nitric acid and add aqueous barium nitrate

Question 26

result for sulfate anion

Answer 26

white ppt

Question 27

test for sulfite anion

Answer 27

add dilute acid, warm gently and test the gas released

Question 28

result for sulfite anion

Answer 28

gas decolorizes purple acidified aqueous potassium manganate (VII) solution