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A student suggested that calcium could b...

A student suggested that calcium could 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))`.

Text Solution

Verified by Experts

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)`
`DeltaG^(@)=-1580-3(-640)=340 kJ=+ ve`

Since `DeltaG^(@)` comes out to be positive, the reaction is not feasible.
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