qualitative analysis: anion tests

Question 1

test for carbonate
CO3 2-

Answer 1

add dilute hydrochloric acid. Pass the gas evolved into limewater (calcium hydroxide)

Question 2

observation for carbonate test

Answer 2

effervescence is observed. the gas evolved forms a white ppt with limewater

Question 3

equation for carbonate test

Answer 3

CO2(g) + Ca(OH)2(aq) –> CaCO3(s) + H2O(l)

Question 4

test for chloride
Cl-

Answer 4

add dilute nitric acid then add aqueous silver nitrate

Question 5

observation for chloride test

Answer 5

a white ppt formed, insoluble in dilute HNO3

Question 6

equation for chloride test

Answer 6

Ag+(aq) + Cl–(aq) –> AgCl(s)

Question 7

test for iodide
I-

Answer 7

add dilute nitric acid then add aqueous silver nitrate

Question 8

observation for iodide test

Answer 8

a yellow ppt formed, insoluble in dilute HNO3

Question 9

equation for iodide test

Answer 9

Ag+(aq) + I-(aq) –> Agl(s)

Question 9

equation for iodide test

Answer 9

Ag+(aq) + I-(aq) –> Agl(s)

Question 10

test for nitrate
NO3-

Answer 10

add aqueous sodium hydroxide, then add aluminium foil. heat the mixture and test the gas evolved with moist red litmus paper

Question 11

observation for nitrate

Answer 11

colourless gas evolved turns moist red litmus paper blue. gas is ammonia

Question 12

test for sulfate
SO4 2-

Answer 12

i) add nitric acid then add aqueous barium nitrate

or

ii) add hydrochloric acid then add aqueous barium chloride

Question 13

observation for sulfate

Answer 13

i) a white ppt formed, insoluble in dilute HNO3
ii) a white ppt formed, insoluble in dilute HCl

Question 14

equations for sulfate

Answer 14

i) Ba2+(aq) + SO4 2-(aq) –>BaSO4(s)
ii)Ba2+(aq) + SO4 2-(aq) –> BaSO4(s)