Question

When a student was given a viscometer, the liquid was sucked with difficulty; the liquid may be
A. Benzene
B. Toluene
C. Water
D. Glycerine

Answer 1

Hint: Viscosity is defined as the ability of the liquid to flow. A more viscous liquid flows at a slower rate and it is difficult to be sucked in the pipette when compared to less viscous liquid and the viscosity of liquids are measured using a viscometer.

Complete step by step answer:
In solids there is a strong attractive force between the molecules, as we heat the solid the attractive force becomes less effective because of increased vibration of molecules. As the attractive force becomes less effective movement relative to each other starts. Application of more and more energy results in more movements and then the solids start converting into liquids, for a given temperature different liquids show different magnitudes of relative movement between molecules. This relative movement is measured by a physical quantity called viscosity. Viscosity is the resistance for the ability of the fluid to flow. A liquid is more viscous when strong forces of attraction and less relative movement of particles and a liquid is less viscous when there are weak forces of attraction and more relative movement. The instrument used to measure viscosity is called a viscometer. When compared to benzene, toluene, water and glycerine. Glycerine is more viscous compared to others thus there will be a difficulty in sucking with the help of viscometer

So, the correct answer is Option D.

Additional information:
Force which prevents the relative movement of particles on layers of liquid is called viscous force. More the viscosity more will be the viscous force. The highly viscous liquids are used in machinery parts as lubricant. The circulation of blood through arteries and veins depends on viscosity of the fluids. Highly viscous liquids are used in hydraulic brakes as brake oil.

Note: When compared to all the fluids thick liquids have got more viscosity and the ones which are less viscous could be easily sucked by the pipette and the viscosity measurements are done with a viscometer along with suitable calculations.