Question

Which of the following processes is spontaneous?

• A. Flow of heat from a colder to a hotter body
• B. Boiling of water
• C. Evaporation of water at room temperature
• D. All of these

Answer 1

The correct option is C Evaporation of water at room temperature

The processes in (a) and (b) are non spontaneous as they require external source of energy i.e. they don't occur on their own spontaneously.
Evaporation of water (c) is a spontaneous process as it does not require any external source of energy, it occurs sponteneously (though very slow) at room temperature.