Give the characteristic tests for the following gases: (i) CO_(2) (ii

1.	Give the characteristic tests for the following gases: (i) CO_(2) (ii) SO_(2) (iii) O_(2) (iv) H_(2)
Answer» Solution :The characteristic test for (i) Carbon dioxide `(CO_(2))` gas TURNS lime water milky when passed throught it due to the formation of insoluble calcium carbonate. `underset("Lime water")(CA(OH)_(2))+underset("dioxide")underset("Carbon")(CO_(2))rarrunderset("carbonate")underset("Calcium")(CaCO_(3))+H_(2)O` (ii) Sulphur dioxide `(SO_(2))` gas when passed through acidic potassium permanganate solution (purple in colour) turns it colourless because `SO_(2)` is a strong reducing agent. `undersetundersetunderset(("Purple"))("permanganate")("Potassium")(2KMnO_(4))+2H_(2)O+underset("dioxide")underset("Sulphur")(5SO_(2))rarrundersetundersetunderset(("Colourless"))("sulphate")("Potassium")(K_(2)SO_(4))+undersetundersetunderset(("Colourless"))("Sulphate")("Manganese")(2MnSO_(4))+2H_(2)SO_(4)` (iii) The EVOLUTION of oxygen `(O_(2))` gas during a reaction can be confirmed by bringing a burning candle near the month of the test tube containing the reaction mixture. The intensity of the flame increases because oxygen supports burning. (iv) Hydrogen `(H_(2))` gas burns with a POP sound when a burning candle is brought near it.

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