Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R
Assertion A: The reduction of a metal oxide is easier if the metal formed is in liquid state than solid state.
Reason R: The value of $$\Delta G^\theta$$ becomes more on negative side as entropy is higher in liquid state than solid state.
In the light of the above statements, choose the most appropriate answer from the options given below

We are given the following statements:

Assertion A: The reduction of a metal oxide is easier if the metal formed is in liquid state than solid state.

Reason R: The value of $$\Delta G^\theta$$ becomes more on negative side as entropy is higher in liquid state than solid state.

In metallurgy, the Ellingham diagram shows how $$\Delta G^\theta$$ for the formation of metal oxides varies with temperature. When a metal melts, there is a sharp change in the slope of its Ellingham line because the entropy of the system changes significantly at the melting point.

The Gibbs free energy equation is $$\Delta G^\theta = \Delta H^\theta - T\Delta S^\theta$$. When the metal is in the liquid state, the entropy $$S$$ of the metal is higher than in the solid state (since liquids have more disorder). This means the entropy change $$\Delta S$$ for the oxide formation reaction becomes more negative (because we are going from a higher-entropy liquid metal to a more ordered oxide).

For the reduction reaction (metal oxide → metal), the reverse applies: the entropy change becomes more positive when the metal product is liquid. This makes $$\Delta G^\theta$$ for the reduction reaction more negative, meaning the reduction becomes thermodynamically more favourable.

So Assertion A is correct — reduction of a metal oxide is indeed easier if the metal formed is in the liquid state. Reason R is also correct — the higher entropy of the liquid state does make $$\Delta G^\theta$$ more negative for the reduction process. Furthermore, R directly explains A, since the higher entropy of the liquid state is the fundamental reason why the reduction becomes easier.

Hence, the correct answer is Option A: Both A and R are correct and R is the correct explanation of A.