The viscosity of liquids decreases with an increase in temperature.

Viscosity is a measure of a liquid's resistance to flow. It determines how easily a liquid can flow or be deformed under an applied force. The viscosity of a liquid depends on various factors including intermolecular forces, temperature, and the nature of the liquid itself.

Intermolecular Forces:
Intermolecular forces are attractive forces between molecules. In liquids, these forces play a significant role in determining the viscosity. Liquids with stronger intermolecular forces have higher viscosity. The intermolecular forces cause the molecules to stick together, making it more difficult for them to move past one another.

Effect of Temperature:
Temperature has a profound effect on the viscosity of liquids. As the temperature increases, the kinetic energy of the molecules also increases. This increased kinetic energy disrupts the intermolecular forces, weakening their effect. Consequently, the molecules can move more freely, reducing the resistance to flow. This results in a decrease in viscosity.

Viscosity and Temperature Relationship:
The relationship between viscosity and temperature can be explained by the Arrhenius equation. According to this equation, the viscosity of a liquid decreases exponentially with an increase in temperature. The equation states that the viscosity (η) is inversely proportional to the absolute temperature (T). Mathematically, it can be represented as:

η = Ae^(Ea/RT)

Where η is the viscosity, A is a constant, Ea is the activation energy, R is the gas constant, and T is the absolute temperature.

Practical Examples:
The effect of temperature on viscosity can be observed in everyday life. For example, honey has a high viscosity at room temperature, making it thick and sticky. However, when heated, the viscosity of honey decreases, and it becomes more fluid. Similarly, motor oil is more viscous at lower temperatures, which is why it is recommended to warm up the engine before driving in cold weather.

Overall, the viscosity of liquids decreases with an increase in temperature due to the weakening of intermolecular forces as a result of increased molecular motion.