Tests For Anions

Question 1

Carbonate (CO3^2-)

Answer 1

Add dilute acid. Heat.

Effervescence (CO2) observed. When bubbled into limewater, white ppt is formed.

Question 2

Chloride (Cl^-) (aqueous)

Answer 2

Acidify with dilute nitric acid. Add aqueous silver nitrate.

White ppt (Silver chloride) formed.

OR

Acidify with dilute nitric acid. Add aqueous lead (II) nitrate. Heat. Cool.

White ppt (Lead chloride) formed. White pot dissolves on heating and reappears as white crystals on cooling.

Question 3

Nitrate (NO3^-) (aqueous)

Answer 3

Acidify with hydrochloric acid. Add aqueous sodium hydroxide. Add aluminum foil (test for nitrate ion). Warm carefully.

Ammonia gas produced.

Question 4

Sulfate (SO4^2-) (aqueous)

Answer 4

Acidify with dilute nitric acid. Add aqueous barium nitrate/fluoride.

White ppt (Barium sulfate) formed.

Question 5

Iodide (I^-)

Answer 5

Acidify with nitric acid. Add aqueous silver nitrate.

Light yellow ppt (Silver iodide) formed.

OR

Acidify with nitric acid. Add aqueous lead (II) nitrate. Heat. Cool.

Bright yellow ppt (lead iodide) formed. Ppt darkens on heating and reappears as yellow crystals on cooling.