Test: Liquid State - Chemistry MCQ

Poise is the unit of viscosity. It’s S.I. unit is 1 Newton second per square meter. It’s Pascal second. In C.G.S. system, the unit of viscosity is poise that is named after a scientist Jean Louise
Poiseuille. So, it’s 1 poise = 0.1 kgm^-1s^-1.

The formula of force required to maintain the flow of layers is given by the formula F = ηAdu/dz, where η is the coefficient of viscosity, A is the area of contact and du/dz is the velocity gradient. So by substituting we get an answer as 0.25dz/du.

Surface Tension is the tendency of a fluid to occupy least surface area as possible. It is defined as the force per unit distance. So, the units of surface tension are Newton/meter in S.I. the system, Dyne/cm in C.G.S system.

Surface Tension is the tendency of a fluid to occupy least surface area as possible. It is defined as the force per unit distance. So, the spherical shape that is acquired by a water drop is due to surface tension.

Viscosity is defined as the resistance to the flow of a liquid. It opposes a liquid’s layer movement with respect to one another. So, the above statement: the higher the viscosity, the slower the liquid flows is true.

The boiling point at pressure 1 atm is known as normal boiling point. Normal boiling point is slightly greater than the standard boiling point as molecules change into the vapor phase and density of vapor increases.

The viscosity of gases increases with temperature, whereas the viscosity of liquids decreases with temperature.

The type of flow in liquids when each path flows in a different path, that do not interfere with each other is laminar flow. At any point in the fluid, the velocity of a fluid is constant is a characteristic of laminar flow.

When the angle of contact between the liquid and container is 90 degrees then the cohesive and adhesive forces in a liquid are equal. Cohesive force is the attraction between similar atoms and adhesive between different atoms.

The surface tension in liquids decreases with rise in temperature. As surface tension decreases, molecules become more active when temperature increases and surface tension becomes zero at critical temperature T_C.