How does acid (vinegar) react with a metal (paperclip)

When and

Explanation:

The spontaneity of a reaction can be determined by the sign of the Gibbs free energy change. For a spontaneous reaction, the change in Gibbs free energy should be negative, meaning:

Since the temperature value here corresponds to the absolute temperature, this implies that T > 0 for any T. Therefore, to have a negative difference for any temperature value, the first term, the change in enthalpy, should be negative and the change in entropy should be positive, so that we always subtract a positive number from a negative number. This corresponds to a negative value in .