Question

$\Delta S_{surr}$ for an exothermic reaction is

• A. always positive
• B. always negative
• C. zero
• D. may be positive or negative

Answer 1

The correct option is D may be positive or negative

Entropy measures disorder. The entropy change accompanying a reaction measures how the reaction affects the orderliness of the system. Other factors being equal, it is the nature of matter to move toward a state of maximum disorder. $\Delta S$ is the may be positive or negative. If a reaction is exothermic ( $H$ is negative) and the entropy $S$ is positive (more disorder), the free energy change is always negative and the reaction is always spontaneous. If the enthalpy change $H$ and the entropy change $S$ are both negative, the spontaneity of the reaction depends on the temperature.