Chemistry Lab Test for Anions

identification test for carbonate ion

Action of dil. HCl

To a little of the substance about 1 mL of dil. HCl solution is added slowly.

observation

vigorous brisk effervesence with evolution of colorless, odourless gas.

presence of carbonate identified.

carbonate confirmatory 1

A little of the substance treated with dil. HCl and the evolved gas is passed through lime water.

observation

lime water turns milky

Presence of carbonate confirmed

carbonate confirmatory 2

To a little of the salt solution barium chloride solution is added

observation

white precipitate formed

carbonate is confirmed

Identification test for Acetate ion

Action of dil. H2SO4

A little of the substance is rubbed with dil. H2SO4 in a watch glass

observation

vinegar like smell

Presence of acetate is identified.

acetate confirmatory 1

To a little of the salt solution one to two drops of neutrall ferric chloride solution is added

observation

deep red coloration

presence of acetate confirmed.

acetate confirmatory 2

A mixture of the salt solution and ethanol is heated with a little conc. H2SO4 in a dry test tube. It is then poured in excess of water.

observation

pleasant fruity smell

acetate confirmed.

Identification test for Chloride ion

Action of conc. H2SO4

To a little of the substance conc. H2SO4 is added in a dry test tube and warmed

observation

colorless gas which gives dense white fumes when glass rod dipped in NH4OH is introduced to the mouth of the test tube

presence of chloride is identified.

chloride confirmatory 1

To a little of the substance few drops of dil. HNO3 and silver nitrate (AgNO3) is added

observation

white curdy precipitate soluble in excess of NH4OH

presence of chloride confirmed.

chloride confirmatory 2

A little of the salf is heated with conc.H2SO4 and a pinch of MnO2

observation

greenish yellow gas with pungent smell

chloride is confirmed.

Identification test for Nitrate ion

A little of the salt is strongly heated with two to three drops of conc. H2SO4. To the boiling solution a paper ball is added.

observation

reddish brown gas evovled

presence of nitrate ion identified.

nitrate confirmatory 1

Brown ring test (ferrous sulphate and conc. H2SO4)

To a little of the salt solution equal volume of freshly prepared ferrous sulphate solution is added and shaken well. To this conc. H2SO4 is carefully added along the side of the test tube.

observation

a brown ring is formed at the junction of the acid and acqueous solution

presence of nitrate ion confirmed.

nitrate confirmatory 2

To a little of the salt solution NaOH and aluminium powder are added

observation

smell of ammonia. Gives dense white fumes with glass rode dipped in conc. HCl.

nitrate is confirmed.

Identification test for Sulphate ion

Action of Barium Chloride sol.

To a little of the salt solution barium chloride solution is added

observation

white precipitate insoluble in dil HCl

presence of sulphate ion is identified.

sulphate confirmatory 1

To a little of the salt solution lead acetate is added

observation

white precipitate

presence of sulphate ion is confirmed.

sulphate confirmatory 2

To the previous precipitate ammonium acetate solution is added

observation

precipitate becomes soluble

sulphate is confirmed.