Question

Which of the following is not a solution
(A) Air
(B) Smoke
(C) Gold ring
(D) Saltwater

Answer 1

Hint: The solution is defined as a homogeneous mixture of solute and solvent. The solute will be present in less quantity and dissolve in the solvent. The solvent will be present in a high amount of quantity. Colloids are also one type of solution in which the particles are of different sizes when compared to the solute.

Complete Step By Step Answer:
Given options are air, smoke, gold ring, and saltwater.
Air is a mixture of different gases like nitrogen, carbon dioxide, and oxygen. Out of all these gases, nitrogen will be present in high amounts. Thus, other gases were dissolved in nitrogen which leads to the fact that air is a solution.
Smoke is the colloidal solution in which the solid particles are dispersed in the gas which is known as dispersed medium.
A gold ring is a mixture of gold, copper, and traces of zinc. Thus, the gold ring is a mixture but not a solution.
Saltwater is the mixture of sodium chloride which is known as salt dissolved in water. Thus, saltwater is considered a true solution.
In the given options air, smoke, and saltwater are considered as solutions, whereas a gold ring is not a solution.
Option C is the correct one.

Note:
The solution is a homogeneous mixture. All the mixtures were not solutions but all the solutions were mixtures. As the gold ring consists of mixtures of elements like copper, gold which is not uniformly distributed leads to the properties of mixture only but not a solution.