Air is a _______________ A. Homogenous mixture B. Heterogeneous mixture C. Compound D. None of these.
Hint: Air is made up of various gases which are distributed uniformly in every part of the atmosphere. If we analyze any section of air, we will find that it’s composition is similar everywhere. All the gases have the same proportions everywhere in the air.
Complete answer: In chemistry, mixtures refers to materials. The homogeneity of a mixture depends on the uniformity and materials of the matter. A homogenous mixture is considered as the mixture which is made up of uniformly distributed components throughout the mixture. It is also considered that homogenous mixtures are those which contain only one phase of matter such as solid, liquid or gas. The components of a homogenous mixture cannot be physically separated easily. Whereas, a heterogeneous mixture is the one where the components are not uniformly distributed. The samples are taken from a heterogeneous mixture that doesn't show uniformity such as cereals in milk. Heterogeneous mixture is always formed from two or more phases of matter. Also, they can be easily separated from each other. Hence, air is made up of various gases such as $78.09%$ Nitrogen, $20.95%$ oxygen, $0.93%$ argon,$0.04%$ carbon dioxide and water vapors. But they all are in single phase. Therefore, the answer is Homogenous mixture. So, the correct answer is “Option A”.
Note: A homogeneous mixture is a solid, liquid or gaseous mixture that has the same proportions of its components throughout the given sample. Conversely, a heterogeneous mixture has components in which proportions vary throughout the sample. Homogeneous and heterogeneous are not absolute terms, but are dependent on context and the sizes of the samples in consideration.