FOR ANIONS
Take a small amount of the substance and add a little volume of dil. HCl (or) dil. H2SO4. Observe the reaction in cold. Warm the contents gently and infer the reactions. | Observation | Inference | Confirmatory Tests | | Brisk effervescence in cold with evolution of colourless and odourless gas | CO32-
(carbonate) | Pass the gas in a test tube containing small quantity of lime water. It turns milky. | | A colourless gas with suffocating odour having smell of burning sulphur | SO32-
(sulphite) | Moisten a piece of filter paper with acidified K2Cr2O7 and put it on the mouth of the test tube. It turns green. | | A colourless gas with smell of rotten eggs | S2-
(sulphide) | Moisten a piece of filter paper with lead acetate solution and place it on the mouth of the test tube. It turns black. | | A light brown gas | NO2-
(nitrite) | a) Pass the evolved gas through FeSO4 solution. It turns brown.
b) Mix the given salt (or) mixture with a little of KI and dil. H2SO4. Evolution of violet vapours
c) Place a piece of filter paper on the mouth of test tube moistened with solutions of starch, KI and acetic acid. It turns blue. | | Colourless vapours with the smell of vinegar | CH3CO2-
(Acetate) | a) To the aqueous solution of substance add neutral FeCl3 solution. A blood red colour is formed.
b) Rub the moistered salt (or) mixture with dry oxalic acid. Smell of vinegar is obtained. |
B) Take a small amount of the substance and add some conc. H2SO4
warm gently, observe the changes and draw inference as follows. | Observation | Inference | Confirmatory Tests | | Colourless gas with pungent smell which fumes in air. Add a pinch of MnO2 in the solution and a pale green gas is evolved. | Cl-
(chloride) | a) Bring a glass rod dipped in NH4OH on the mouth of the test tube; white fumes are formed.
b) Bring a glass rod dipped in AgNO3 solution on the mouth of the test tube; white curdy precipitate is formed on the rod.
c) To the substance in a dry test tube add three times its weight of powdered K2Cr2O7 and conc. H2SO4. Heat the contents. Red vapours are evolved. Pass the vapour in a test tube containing NaOH solution. A yellow precipitate appears. | | Reddish brown fumes which intensify on addition of MnO2. Vapours passed in water make it yellow | Br-
(Bromide) | a) Take aqueous extract of the substance (or) extract with dil. HNO3 and add. AgNO3 solution. A light yellow precipitate appears.
b) To a small amount of the substance add dil. H2SO4. Warm and cool. Add 1 mL of CHCl3 (or) CCl4 and then chlorine water with constant shaking. The chloroform layer becomes orange brown. | | Violet pungent fumes evolved which may condense as black specks on the cooler parts of the test tube. The violet fumes intensify on addition of MnO2. | I -
(Iodide) | a) Place a piece of filter paper moistered with starch solution on the mouth of the test tube. The paper turns blue.
b) Take aqueous extract of the substance and add AgNO3 solution. Yellow precipitate is formed which is insoluble in NH4OH solution.
c) To the small amount of the substance add dil. H2SO4 and 1 mL of either CHCl3 (or) CCl4 and then Cl2 water with constant shaking. Chloroform layer attains violet colour. | | Light brown vapours having pungent smell. It intensifies on adding copper turnings. | NO3-
(Nitrate) | Take an aqueous extract of the substance in a test tube and add freshly prepared FeSO4 solution. Add conc. H2SO4 by the side of the test tube without disturbing the solution. A brown ring is formed at the junction of two liquids. | | Colourless, odourless gas which burns with blue flame at the mouth of the test tube and turns time water milky | C2O42-
(Oxalate) | Take the substance, add dil. H2SO4 and heat till there are no more effervescences. Now add MnO2 (solid) and brisk effervescences is obtained. |
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