Colloids, Emulsion, Gel and Their properties with application Questions in English

(D) $1$. Lyophilic colloids are 'solvent-loving' colloids.
$2$. They have a strong affinity between the dispersed phase and the dispersion medium.
$3$. They are reversible in nature, meaning they can be easily reformed by simply mixing the dispersed phase with the dispersion medium after evaporation.
$4$. They are formed by direct mixing or warming.
$5$. Therefore, the correct statement is that it is a solvent-loving colloid.

(A) $1$. Macromolecular colloids are substances that have large molecular masses and form colloidal solutions when dispersed in a suitable solvent.
$2$. Examples include naturally occurring polymers like proteins, starch, and cellulose, as well as synthetic polymers like polyethylene and nylon.
$3$. Detergents and soaps form associated colloids (micelles) at higher concentrations.
$4$. $S_8$ sulphur molecules form multimolecular colloids.
$5$. Therefore, proteins are the correct example of macromolecular colloids.

(C) $1$. Electrophoresis is the phenomenon of movement of colloidal particles under an applied electric field.
$2$. In this process, the sol particles migrate towards the oppositely charged electrode.
$3$. By measuring the velocity of these particles in a known electric field, the rate of migration can be determined.
$4$. Therefore, electrophoresis is used to measure the rate of migration of sol particles.

(B) Step $1$: Analyze the given conditions. The movement of colloidal particles under an applied electric field is known as electrophoresis.
Step $2$: Evaluate the options. Dialysis involves the movement of ions through a semipermeable membrane. Electroosmosis refers to the movement of the dispersion medium under an electric field. Brownian motion is the random zigzag movement of particles.
Step $3$: Conclude that the correct term for the movement of colloidal particles under an electric potential is electrophoresis.

(B) Hard water contains dissolved salts of calcium $(Ca^{2+})$ and magnesium $(Mg^{2+})$ ions.
When soap (sodium or potassium salts of long-chain fatty acids) is added to hard water, these ions react with the soap to form insoluble precipitates known as $Scum$.
This process prevents the soap from forming a lather, making it ineffective for cleaning in hard water.