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An element 'A' exists as a yellow solid in standard state. It forms a volatile hydride 'B' which is a foul smelling gas and is extensively used in qualitative analysis of salts. When teated with oxygen, 'B' forms an oxide 'C' which is a colourless, pungent smelling gas. This gas when passed through acidified KMnO_(4) solution, decolourises it. 'C' gets oxidised to another oxide 'D' in the presence of a heterogeous catalyst. Identify A, B, C, D and also give the chemical equation of reaction of 'C' with acidified KMnO_(4) solution and for conversion of 'C' to 'D'. |
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Answer» Solution :(i) SINCE element 'A' is a yellow solid in the standard state and forms a foul smelling gas 'B' which is extensively USED in qualitative analysis of salts, therefore, the element 'A' must be sulphure `(H_(2)S)`. `UNDERSET(("Yellow solid, A"))underset("Sulphur")(S) + H_(2) overset("Heat")rarr underset(("Foul smelling gas, B"))underset("Hydrogen sulphide")(H_(2)S)` (ii) Since the volatile gas 'B' reacts with OXYGEN to form a colourless pungent smelling gas 'C' which decolourises acidified `KMnO_(4)` solution, the gas 'C' must be sulphur dioxide `(SO_(2))`. `underset("Hydrogen suphide (B)")(2H_(2)S) + 3O_(2) rarr 2 H_(2)O + underset(("Colourless pungent smelling gas C"))underset("Sulphur dioxide")(2SO_(2))` The gas C being a reducing agent reduces acidified `KMnO_(4)` solution. `{:(""2KMnO_(4)+3H_(2)SO_(4) rarr K_(2)SO_(4)+2MnSO_(4)+3H_(2)O+5[O]),(""SO_(2)+H_(2)O+[O] rarr [H_(2)SO_(4)] xx 5),(bar(underset(("Pink"))(2KMnO_(4))+5SO_(2)+2H_(2)rarr K_(2)SO_(4)+underset(("Colourless"))(2MnSO_(4))+2H_(2)SO_(4))):}` (iii) Since the colourless pungent smelling gas 'C', i.e., `SO_(2)`, can be oxidised to another oxide 'D' in the presence of a heterogeneous CATALYST (i.e., Pt or `V_(2)O_(5)`), therefore, the oxide 'D' must be sulphur trioxide `(SO_(3))`. `underset("Sulphur dioxide (C)")(2SO_(2)) + O_(2) rarr underset("Sulphur trioxide (D)")(2SO_(3))` Thus, 'A' is sulphur (S), 'B' is hydrogen sulphide, `(H_(2)S)`. 'C' is sulphur dioxide `(SO_(2))` and 'D' is sulphur trioxide `(SO_(3))`. |
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