- For a pure substance undergoing vaporization, the change in Gibbs free energy is negative, indicating that the process is spontaneous under normal conditions.
Conclusion: The change in Gibbs free energy for vaporization is negative, as given by option (B).
A gaseous reaction \( A \to 2B + C \) takes place isothermally in a constant pressure reactor. Starting with a gaseous mixture containing 50% A (rest inerts), the ratio of final to initial volume is found to be 1.6. The percentage conversion of A is