Question

Which of the following are colloids?
A.Milk
B.Ice cream
C.Urea solution
D.blood

Answer 1

Colloids are defined as the mixtures in which microscopically dispersed insoluble particles of one substance are suspended into another substance. The minute particles that get dispersed into other substances are known as colloidal particles.

Complete step by step answer:
Colloids are also referred to as colloidal dispersions because the substance remains dispersed but does not settle down at the bottom.
The size of the particle ranges from $1 - 1000nm$ in diameter.
Even though the particle size is very small it gets distributed evenly throughout the solution.
The majority of the colloids have the following characteristics:
Thermal kinetic energy helps them to move easily.
Type of interactions due to electromagnetic radiations.
Here are some of the examples of the colloids as follows:
Milk is considered as one of the best examples of colloids.
Shampoo, liquid hand wash, ice cream, blood, cloud and many more.
Milk: In milk liquid fat globules are dispersed in water, that is why it is considered as colloids.
Ice cream: it is a complex food colloid that consists of fat globules, air bubbles ice crystals, thus ice cream is a colloid.
Urea solution: in this solution there is no insoluble substance present and is a true solution, that is why it is not considered as colloid.
Blood: in blood the size of blood cells ranges between $1 - 100nm$ , also it is a sol. Therefore it is a colloid.
So, the correct answers are option a) milk, option b) ice cream and option d) blood.
Applications of colloids;
-It is used in the medicinal field.
-In food items such as halwa, soup.
-Tanning of leather.

Note: Sol is a colloid that is made up of very minute particles present in the continuous liquid solution. Colloids are heterogeneous in nature. Colloids also show some tyndall effect. Tyndall effect is light scattering in a colloid or in a fine suspension.