Question

Viscosity of liquids ___ with an increase in temperature and the viscosity of gases ___ with an increase in temperature.

• A. increases, increases
• B. decreases, increases
• C. decreases, decreases
• D. increases, decreases

Answer 1

The correct option is B

decreases, increases

For liquids, viscosity is due to the intermolecular forces. When we increase the temperature, the molecules acquire higher energy and thus intermolecular forces are weakened. Hence, the viscosity of liquids decreases with increase in temperature. For gases, viscosity is due to collision between gas molecules. With increase in temperature, gas molecules attain more kinetic energy and the rate of collision is more. Hence, viscosity of gases increases with increase in temperature.