Question

Increase in the kinetic energy can overcome intermolecular forces of attraction. How will the viscosity of liquid be affected by the increase in temperature?
(A) Increase
(B) No effect
(C) Decrease
(D) No regular pattern will be followed

Answer 1

Hint: To solve this question, we should know the relation between kinetic energy and temperature variation. Further we should be aware whether the viscosity varies with temperature or kinetic energy directly or inversely.

Complete step by step answer
Before starting with the answer, let us get familiar with some terms.
Kinetic energy: energy possessed by the body by being in the virtue of motion.
Viscosity: in layman language, we can say how easily liquids flow, for example- water flows more easily than honey. This example leads us to a conclusion that water is less viscous than honey. In a proper way we can quote viscosity of a liquid as its tendency to resist the deformation at a given rate.
Coming to the solution of the question,
When the temperature increases, the kinetic energy of the molecules increases which is the result of decrease in force of attraction. The molecules overcome the force of attraction(in general intermolecular forces) so that they can slide past one another between different layers.
So, with the increase in temperature of the system, the kinetic energy increases and intermolecular forces decrease that results in the decrease of viscosity.
Hence option C is the correct option to the given answer.

Note
One should keep in mind that temperature and kinetic energy are directly proportional to each other, that is, if the temperature of the system increases, kinetic energy of the system will automatically increase. We can also conclude that the momentum of the system increases with increase in temperature.