Give the characteristic tests for the following gases : (a) CO_(2)(b)

1.	Give the characteristic tests for the following gases : (a) CO_(2)(b) SO_(2) (c) O_(2)(d) H_(2)
Answer» Solution :(a) `CO_(2)` gas : It is a COLOURLESS and odourless gas. When passed through lime water, it will initially become milky. `Ca(OH)_(2)(aq) + CO_(2)(g) + H_(2)O(aq) to underset("(Colourless)")(Ca(HCO_(3))_(2)(aq))` (b) `SO_(2)` gas : It is a colourless but a pungent smelling gas. The gas when passed through an acidified solution of potassium permanganate (pink) will decolourise it. `underset("(Pink)")(2KMnO_(4)) + 5SO_(2) + 2H_(2)O to K_(2)SO_(4) + 2MnSO_(4) + 2H_(2)SO_(4)` Similarly, the gas when passed through an acidified solution of potassium dichromate (orange) will make it light green. `underset("(Orange)")(K_(2)Cr_(2)O_(7)) + 3SO_(2) + H_(2)SO_(4) to K_(2)SO_(4) + underset("(Light green)")(Cr_(2)(SO_(4))_(3) +) H_(2)O` (c) Oxygen gas : The gas is a supporter of combustion. It can be TESTED by bringing a burning or smouldering match-stick near the MOUTH of the test tube from which the gas escapes. The match-stick will burn more brightly. (d) Hydrogen gas : The gas itself is COMBUSTIBLE. It will burn with a pop sound when a burning candle or match-stick is brought near it. `2H_(2)(g) + O_(2) (g) to 2H_(2)O(g)`

Discussion