Dry Test Analysis for action of dilute Sulphuric Acid

 

Treat 1 gm of the mixture with about 2 cm³ of dilute H₂SO₄ and note weather any reaction takes place in the cold. Warm the mixture and observe the effect produced.

Observations	Interferences
Colorless gas is evolved with effervescences; gas is odourless and produces a turbidity when passed into lime water.	CO2 from Carbonates or bicarbonates. (CO3’’; HCO3’)
Nitrate oxide fumes evolved, recognized by reddish-brown colour. Turns starch-KI paper bluish-black.	NO2 from Nitrite. (NO2’)
Colorless gas evolved with suffocating odour, turn filter paper moistened with K2Cr2O7­­; green, decolorizes fuchsin solution.	SO2 from SO3’’.
Colourless gas evolved, gives above tests for SO2, Sulphur is deposited in the solution.	SO2 and S from thiosulphate. (S2O3’’)
Colourless gas evolved; odour of rotten eggs, blackens filter paper moistened with lead acetate solution.	H2S from sulphide. (S’’)