Naphthalene can be separated from sand by

The correct option is A

sublimation

The explanation for the correct option:

(a) Sublimation:

1. The process in which a solid directly changes into the gaseous state without changing into liquid form is called sublimation.
2. Examples of solids that sublime is ammonium chloride, camphor, and naphthalene.
3. Naphthalene is a sublimable substance.
4. On heating the mixture of naphthalene and sand, naphthalene sublimes and is deposited on the edges of the flask while sand is left behind.
5. Sublimation can be used to separate naphthalene from the sand.

The explanation for the correct option:

(b) Distillation:

1. When two miscible liquids have boiling point differences of more than $25°\mathrm{C}$ then distillation process is used.
2. In this process, the liquid is heated to its boiling point so that it is converted into vapors.
3. On cooling the vapors, the pure liquid is obtained and collected separately.
4. A mixture of acetone with water can be separated by this method.

(c) Centrifugation:

1. It is a method of separating the suspended particles of a substance from a liquid in which the mixture is rotated at a high speed in a centrifuge.
2. The principle of this process is that the denser particles are forced to the bottom and the lighter particles stay at the top when spun readily.
3. Cream from milk can be obtained by the process of centrifugation.

(d) Evaporation:

1. It is the process of separating any substance from its solution by removing water.
2. For example, it is used to separate soluble components like common salt from the salt solution.

Hence, option (a) is the correct option.