Question

Assertion A: Magnesium can reduce Al₂O₃ at a temperature below 1350°C, while above 1350°C aluminium can reduce MgO.

Reason R: The melting and boiling points of magnesium are lower than those of aluminium.
In light of the above statements. choose most appropriate answer from the options given below:

Options

• Both A and R are correct and R is correct explanation of A.

• Both A and R are correct. but R is not the correct explanation of A.

• A is correct but R is not correct.

• A is not correct but R is correct.

Answer 1

Both A and R are correct. but R is not the correct explanation of A.

Explanation:

From Ellingham diagram, it can be seen that Mg, MgO line crosses Al, Al₂O₃ line after 1350°C i.e., Al can reduce MgO hence assertion is true.

Yes, Mg has lower MP and BP than aluminium but the reduction of one compound by another is governed by the change in Gibbs free energy (ΔG°) of the process.