Emulsions and gels

26 questions on Emulsions and gels from the Surface Chemistry chapter: 5 NEET level, 8 JEE Main, 13 JEE Advanced. Each one opens with its answer and solution.

• Milk is a colloidal system of the type: NEET level
• A gel is a colloidal system in which: NEET level
• Which of the following can act as an emulsifying agent to stabilise an oil-in-water emulsion? NEET level
• A drop of a water-soluble dye is added to an emulsion and it colours the whole emulsion uniformly. The emulsion is of the type: NEET level
• The slow oozing out of liquid from a gel on standing is called: NEET level
• An emulsion mixes readily with water in all proportions and conducts electric current well when electrodes are dipped in it. It is most likely: JEE Main level
• Which of the following would NOT help in breaking (demulsifying) an emulsion? JEE Main level
• Which of the following is a non-elastic gel? JEE Main level
• Certain gels liquefy to a sol on shaking and set again to a gel on standing. This behaviour is known as: JEE Main level
• An emulsion is made from 40 mL of oil (density 0.80 g/mL) and 160 mL of water (density 1.00 g/mL). Find the mass percentage of oil in the emulsion (two decimals... JEE Main level
• A gelatin gel contains 4.0% gelatin by mass and has density 1.02 g/mL. Find the mass of gelatin, in grams, present in 250 mL of this gel (two decimals). JEE Main level
• Select the correct statement(s) about emulsions. JEE Main level
• Select the system(s) that are gels. JEE Main level
• 14 mL of oil is dispersed in water as spherical droplets of uniform radius 0.60 micrometre. The oil-water interfacial tension is 0.038 N/m. Neglecting the area ... JEE Advanced level
• An agar gel containing 2.0% agar by mass is to be prepared. The agar powder available is 92% agar by mass (the rest is moisture). What mass of the powder, in gr... JEE Advanced level
• 200 mL of an oil-in-water emulsion contains 30.0% oil by volume (oil density 0.85 g/mL). 300 mL of water (density 1.00 g/mL) is added and the emulsion is mixed.... JEE Advanced level
• An oil-in-water emulsion is stabilised by sodium stearate. Dilute hydrochloric acid is added in excess and the emulsion breaks. The best explanation is: JEE Advanced level
• A fixed volume of oil is dispersed in water as identical spherical droplets. If the droplet radius is halved, the number of droplets and the total interfacial a... JEE Advanced level
• Using the usual convention for the dispersed phase and the dispersion medium (dispersed phase first), which row lists all three systems correctly? JEE Advanced level
• Which statement about a gelatin gel is INCORRECT? JEE Advanced level
• Pure oil and pure water shaken together separate into two layers again on standing, but with a small amount of soap the dispersion persists. The main reason for... JEE Advanced level
• An emulsion mixes freely with kerosene but forms two separate layers when shaken with water. A water-soluble dye added to it colours only small droplets. The em... JEE Advanced level
• 8.0 mL of oil is dispersed in water as identical spherical droplets of radius 2.0 micrometre (use pi = 3.14). Select the correct statement(s). JEE Advanced level
• Select the correct statement(s) about gels. JEE Advanced level
• Select the correct statement(s) about emulsifying agents. JEE Advanced level
• For emulsions, select the correct statement(s) about the type of the emulsion. JEE Advanced level