Which of the following statements about evaporation and boiling is FALSE?

Step 1: Analyze the question We need the FALSE statement about evaporation and boiling. So we check each option against what we know.

Step 2: Key concepts

• Evaporation: occurs at any temperature, only at the surface, and its rate increases with temperature, surface area, dryness of the surrounding air, and air movement.
• Boiling: occurs at a fixed temperature (the boiling point) for a given pressure, throughout the liquid, and the boiling point changes with external pressure.

Step 3: Check each option

• A. Evaporation may take place at any temperature. TRUE. Wet clothes dry on cold days too.
• B. In evaporation, vapour escapes only from the surface. TRUE. This is the main difference from boiling, where bubbles form throughout the liquid.
• C. The temperature remains constant as long as the liquid is boiling. TRUE. The heat supplied goes into latent heat of vaporisation, not a temperature rise (for a pure liquid at constant pressure).
• D. Boiling temperature can be altered by changing the external pressure. TRUE. Water boils below 100 °C at high altitude (lower pressure), and above 100 °C in a pressure cooker (higher pressure).
• E. The rate of evaporation does not depend on temperature. FALSE. Higher temperature gives molecules more kinetic energy, so more of them escape the surface. This is why clothes dry faster on a hot, sunny day in Nigeria than on a cool harmattan morning.

Step 4: Answer

Tip: In "which is false" questions, watch for absolute words like "only," "does not," and "never." Here, "does not depend on temperature" contradicts the well-known factors affecting evaporation (temperature, surface area, humidity, wind).