Question

Why viscosity of gasses increases with temperature where as viscosity of liquid decreases with temperature?

Please Explain

Answer 1

viscosity in liquid is mainly because of cohesive force(inter molecular force of attraction). when there is an increase in the temperature this reduce the cohesive forces between the molecules of liquid, hence the value viscosity decreases.
whereas in case of gasses viscosity is mainly due to the random moments of the gaseous molecules.
when temperature of gas is increased the internal energy of the molecules increases, this leads to increased random moment. hence, the viscosity of gases decrease.