Question

The reaction $Cr_2O_3 + 2Al \to Al_2O_3 + 2Cr (\Delta G^? = - 421\, kj)$ is thermodynamically feasible due to -ve value of $\Delta G$. Why does this reaction not take place at room temperature?

• A. Certain amount of activation energy is essential for thermodynamically feasible reactions also
• B. Due to high melting point of chromium oxide the reaction does not take place
• C. Overall value of $\Delta G$ for the net reaction becomes positive
• D. Molecules of $Cr_2O_3$ and $Al$ are not oriented properly

Answer 1

Answer: (A)

Certain amount of activation energy is essential for thermodynamically feasible reactions also

Answer 2

The spontaneous reaction also requires a certain amount of activation energy therefore heating is required.