In an exothermic process, the change in enthalpy is

In an exothermic process, the change in enthalpy is

• A. Positive.
• B. Zero.
• C. Depends on pressure.
• D. Negative.

Answer: (D)

In an exothermic process, the enthalpy change is negative. Enthalpy change represents the heat exchanged with the surroundings at constant pressure, ΔH = q_p. When the system releases heat, the heat flow is out of the system, so q_p is negative, making ΔH less than zero. This reflects the system ending up with a lower enthalpy after the process. The other options don’t fit because positive would mean heat is absorbed (endothermic), zero would imply no heat transfer at constant pressure, and dependence on pressure isn’t what determines the sign for an exothermic change.

In an exothermic process, the enthalpy change is negative. Enthalpy change represents the heat exchanged with the surroundings at constant pressure, ΔH = q_p. When the system releases heat, the heat flow is out of the system, so q_p is negative, making ΔH less than zero. This reflects the system ending up with a lower enthalpy after the process. The other options don’t fit because positive would mean heat is absorbed (endothermic), zero would imply no heat transfer at constant pressure, and dependence on pressure isn’t what determines the sign for an exothermic change.