Answer:an ice cube melting ∆H=+ve
nail polish remover quickly evaporating after it is accidentally spilled on the skin ∆H=-ve
gasoline burning within the cylinder of an automobile engine ∆H=-ve
Explanation:
In an endothermic process, such as the melting of an ice cube, heat is absorbed from the surrounding. The enthalpy change is positive. The evaporation a nail polish and burning of gasoline are exothermic processes which lead to the release of heat to the surrounding. The sign of the enthalpy change in both cases is negative.