Enthalpy change is always negative for which one of the following processes?

Question

Enthalpy change is always negative for which one of the following processes? (A) Enthalpy of ionisation (B) Enthalpy of vapourisation (C) Enthalpy of sublimation (D) Enthalpy of fusion

Tardigrade Admin · Accepted Answer

Combustion reaction will always occur when a substance reacts with oxygen from air to release energy. Since, heat is released for combustion reaction, the enthalpy change of the system, Delta H will be negative always.

Q. Enthalpy change is always negative for which one of the following processes?

Enthalpy of ionisation

Enthalpy of vapourisation

Enthalpy of sublimation

Enthalpy of fusion

Enthalpy of combustion

Combustion reaction will always occur when a substance reacts with oxygen from air to release energy. Since, heat is released for combustion reaction, the enthalpy change of the system, Delta $H$ will be negative always.