With the rise of temperature, the viscosity of liquid :

The correct answer is Decreases.

Key Points

• Viscosity
  • It is often referred to as the thickness of a fluid.
  • It is defined as the measure of the resistance of a fluid to gradual deformation by shear or tensile stress.
  • It is a result of the interaction between the different molecules in a fluid.
  • This can be also understood as friction between the molecules in the fluid.
• There are numerous ways to measure viscosity. One of the most elementary ways is to allow a sphere, such as a metal ball, to drop through a fluid and time the fall of the metal ball: the slower the sphere falls, the greater the viscosity that is measured.
• The viscosity of a liquid decreases rapidly as the temperature increases.
• In liquid, the main cause of viscosity is a collision between that molecules. 
• With the increase in temperature, this collision force decreases as the energy of particles become more, hence movement becomes free and easy.