Question

Which of the following are homogeneous in nature?
(i) ice (ii) wood (iii) soil (iv) air

• A. (i) and (iii)
• B. (ii) and (iv)
• C. (i) and (iv)
• D. (iii) and (iv)

Answer 1

The correct option is C

(i) and (iv)

1. Homogeneous mixtures - A mixture is said to be a homogeneous mixture if it has the same composition throughout the sample.
2. A homogeneous mixture has no visible boundaries of separation between various constituents.
3. Examples of salt solution (sodium chloride is dissolved in water), and sugar solution (sugar dissolved in water).
4. Heterogeneous mixtures - A mixture is said to be a heterogeneous mixture if it consists of two or more parts ( called phases ) that have a different composition.
5. It has visible boundaries of separation of various constituents.
6. Example- salt and sulfur, a mixture of iron and sulfur, smoke (a mixture of air and carbon particles)

An explanation for the correct option:

Ice:

1. It is a solid state of water.
2. The particles are distributed uniformly within them.
3. Thus, ice is an example of a homogeneous mixture.

Air:

1. In the air, all gases would have a uniform composition.
2. It is a mixture of different gases because it contains different gases like oxygen, nitrogen, carbon dioxide, argon, etc
3. Therefore, the air is an example of a homogeneous mixture.

Since ice and air both are homogeneous mixtures thus option (c) is correct.

An explanation for incorrect options:

Wood:

1. All the compounds and elements in the wood are not distributed evenly.
2. Different types of wood vary in composition, density, moisture content, weight, and more.

Soil:

1. Soil is made up of two or more particles.
2. Hence, it comprises more than one phase.
3. Within the same soil the particle's shape, size, and proportion vary.
4. Organic matter like air, water, and minerals also vary

Since wood and soil are heterogeneous mixtures thus options (a),(b), and (d) are incorrect.

Hence, option (c) is the correct option.