Question

which of the following is a mixture?
A. Air
B. Alloys
C. Both A and B
D. None of the above

Answer 1

Hint: A mixture is a material made up of two or more different substances which are physically combined, that no chemical change is occurring between them. They are stable and well mixed having no problem of instability.

Complete Step by step answer: A mixture is the physical combination of two or more substances in which the identities of each substance are retained. Any time two or more items are combined, a mixture is formed until and unless a chemical reaction occurs. Mixtures can be of two types- homogeneous mixture and heterogeneous mixture.
Air is a homogeneous mixture of the gaseous substances like nitrogen, oxygen, smaller amounts of other gases and substances, and identities or chemical properties of all the gases and substances always remain the same, that is no chemical reaction is occurring there. That means they physically combined, hence air is a mixture.
An alloy is a material composed of two or more metals or a metal and non metal. It may be a solid solution of the elements of single phase or mixture of two or more metallic phases. Alloys are used where their properties are superior to those of pure component elements. Some examples are- steel, solder, brass, amalgam etc.

So the correct answer is C. both air and alloy are mixture.

Note: Despite the fact that there is no chemical change occurring to the constituents of the mixture, the physical properties of the mixture, such as melting point, may differ from those of the components. Some mixtures can be separated by using physical means.