Evaporation vs Boiling

At point D, water reaches its boiling point (100 °C at 1 atm). During the D → E segment, all heat supplied goes into breaking intermolecular bonds — this is the latent heat of vaporisation. The temperature remains constant at 100 °C until every molecule of liquid water has converted to steam.

Once all the water has boiled away (point E), continued heating raises the steam temperature above 100 °C. The temperature now increases faster because the specific heat capacity of steam (~2010 J kg⁻¹ K⁻¹) is less than that of liquid water (~4186 J kg⁻¹ K⁻¹).

Yes, absolutely. Once all the liquid water has boiled away, the steam (water vapour) is free to absorb more heat and its temperature rises above 100 °C. This is called superheated steam.

• 100 °C is not a "maximum temperature" for water — it is simply the boiling point at 1 atm pressure where the liquid-to-gas phase change occurs.
• In industrial steam turbines and power plants, superheated steam routinely reaches 200–600 °C.
• Superheated steam is completely dry (no water droplets) and is more efficient for energy transfer in turbines.
• At higher pressures, water can remain liquid even above 100 °C — in a pressure cooker, water boils at approximately 120 °C.

Both evaporation and boiling convert liquid into gas, but they are fundamentally different processes governed by different molecular mechanisms.

Fig.:Evaporation is a surface phenomenon; Boiling occurs throughout the bulk liquid

• Clothes Dry Faster When Spread Out: Spreading clothes increases surface area, so evaporation is faster.
• Spirit on Skin Feels Cool: Alcohol evaporates quickly and absorbs heat, causing a cooling feeling.
• Puddles Dry on Hot Days: Water evaporates into vapour, especially faster in heat and wind.
• Clay Pot Keeps Water Cool: Water evaporates through the pot’s pores, removing heat and cooling the water.
• Humid Days Feel Hotter: In humid air, sweat evaporates slowly, so the body cools less.