Question

Explain why a mixture of zinc oxide and magnesium reacts when heated while there is no reaction when a mixture of zinc and magnesium oxide is heated

Answer 1

Magnesium is a more active metal than zinc. That is, Mg will undergo oxidation (loss of electrons) more readily than Zn which in ZnO would gain the electrons donated by Mg. The MgO bond is more stable than the ZnO bond which resists replacement by less active metals such as Zn. A review of 'The Activity Series' of reactive metals and 'Single Replacement Reactions, is suggested.

Answer 2

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Answer 3

Magnesium is more reactive than zinc hence when Mg is reacted with ZnO, it is oxidised while ZnO is reduced to Zn this the name redox reaction. When MgO is reacted with Zn nothing happens since Mg is more reactive than Zn and Zn cannot be oxidised while MgO cannot be reduced to Mg