Viscosity is the internal friction in a fluid which occurs due to diffusion of molecules of one layer into other. Viscous force opposes the motion of one portion of a fluid relative to other. So, viscous force is due to cohesion between the fluid molecules and transfer of momentum between them. Surface tension is the property of the liquid at rest by virtue of which a liquid tends to occupy minimum surface area and behaves like stretched membrane. It also depends upon the cohesive force. Since, intermolecular cohesive force decreases with the rise in temperature. Hence, with the increase in temperature, viscosity and surface tension of the liquid decreases.