Question

Which of the following is not a mixture?

• A. air
• B. seawater
• C. pure water
• D. soil

Answer 1

The correct option is C

pure water

The correct option is C.

The explanation for the correct answer:

1. A mixture refers to a substance, which is formed of two or more components mixed together physically not chemically.
2. A mixture can be homogenous or heterogeneous.
3. A homogeneous mixture is a mixture in which the components mix with each other and its composition is uniform all through the solution.
4. A heterogeneous mixture refers to the mixture in which the composition is not uniform all through and distinct components can be witnessed.
5. Pure water or distilled water is not a mixture.
6. Pure water is a kind of water in which no other impurities or components are present, that is, only molecules of water are present.
7. Water is a pure substance or compound formed of oxygen and hydrogen.
8. A mixture would be water with other things dissolved in it physically.

The explanation for the incorrect options:

Option A:

1. Air is a mixture, not a compound.
2. It is a mixture of gases like oxygen, nitrogen, nitrous oxide, methane, etc.
3. Air is considered a mixture as the gases retain their characteristics when separated by the process of fractional distillation.

Option B:

1. Sea water is a mixture of pure water and dissolved ionic substances.
2. When the water in the seawater evaporates one can see salt behind.
3. Sea water is a homogenous mixture of water and sodium chloride ions.

Option D:

1. Soil is a mixture of dead and living organisms, minerals, water, and air.
2. Soil is a heterogeneous mixture.

Final answer: Pure water is not a mixture.