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A student suggested that calcium colud be obtained by reducing dolomite `(CaCO_(3).MgCO_(3))` with aluminium powder. Was he correct in his approach ? (Given ` Delta_(f)G^(@) (CaO)=-640.0 " kJ mol"^(-1), Delta_(f)G^(@) Al_(2)O_(3)(s)=-1580.0 " kJ mol"^(-1))`. |
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Answer» No, he was wrong in his approach as is evident from the value of `DeltaG^(@)` for the reaction : `underset(("From dolomite"))(3CaO(s)+2Al(s)) overset("heat") to Al_(2)O_(3) (s) +3Ca(s)` `DeltaG^(@)= Delta_(f)G^(@)(Al_(2)O_(3))-3Delta_(f)G^(@)(CaO)` `=-1580-3(-640)=340 kJ=+ ve` Since `DeltaG^(@)` comes out to be positive, the reaction is not feasible. |
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