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Predict the conditions under which Al might be expected to reduce MgO. |
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Answer» Solution :The Equations for the formation of two oxides are `(4)/(3)Al_((s))+O_(2_((g)))rarr(2)/(3)Al_(2)O_(3),2Mg_((s))+O_(2_((g)))rarr2MgO_((s))` from the Ellingham diagram the two curves of these oxides formation INTERSECT each otherat a certain point .The corresponding value of `DELTAG^(@)` becomes Zero for the reducction of MgO by aluminium metal, `2MgO_((s))+(4)/(3)Al_((s))hArr2Mg_((s))+(2)/(3)Al_(2)O_(3_((S)))` `rarr` From the above INFORMATION the REDUCTION of MgO by Al metal connot occur below this temperature (1665 K) instead , Mg can reduce `Al_(2)O_(3)` to Al below 1665 K. `rarr` Al-Metal can reduce MgO to Mg above 1665K becouse `DeltaG^(@)` for `Al_(2)O_(3)` is less compared to that of MgO. `3MgO_((s))+2Al_((s))overset(Tgt1665K)rarrAl_(2)O_(3(s))+2Mg_((s))` |
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