Chemistry - Metallurgy Question with Solution | TestHub

$T_1$ and $T_2$ are the melting and boiling points of Mg metal (not MgO) because phase changes of the metal increase its entropy, making the reaction entropy ($\Delta S$) more negative and the slope ($-\Delta S$) steeper.

Reduction of MgO by coke (C) is thermodynamically feasible above $T_3$ because the line for CO formation lies below the MgO line, making the net $\Delta G^{\circ }$ negative.

After the $T_2$ point, $|\Delta G^{\circ }|$ for MgO formation decreases because the curve slopes sharply upwards towards zero, meaning $\Delta G^{\circ }$ becomes less negative.

Thus, statements (A), (B), and (C) are correct.