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(i) CO is more stable at higher temperature. Why ? (ii) How will you prepare potash alum ? |
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Answer» Solution :(i) In the Ellingham diagram, the formation of carbon monoxide is a straight line with NEGATIVE slope. In this case `Delta S` is positive as 2 moles of CO gas is formed by the consumption of one mole oxygen. Hence, CO is more stable at higher temperature. (ii) The alunite the alum stone is the naturally OCCURRING form and it is `K_(2) SO_(4). Al_(2) (SO_(4))_(3). 4Al(OH)_(3)`. When alum stone is treated with excess of sulphuric acid, the aluminum hydroxide is converted to aluminium sulphate. A calculated quality of potassium sulphate is added and the solution is crystallised to generate potash alum. It is purified by RECRYSTALLISATION. `K_(2)SO_(4).Al_(2)(SO_(4))_(3).4Al(OH)_(3) + 6H_(2)SO_(4) rarr K_(2)SO_(4) + Al_(2) (SO_(4))_(3) + 12 H_(2)O` `K_(2)SO_(4) + Al_(2) (SO_(4))_(3) + 24H_(2)O rarr K_(2)SO_(4).Al_(2) (SO_(4))_(3).24H_(2)O` |
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