Sodium amalgam, commonly denoted Na(Hg), is an alloy of mercury and sodium. The term amalgam is used for alloys, intermetallic compounds, and solutions (both solid solutions and liquid solutions) involving mercury as a major component.

Explanation:
Amalgam is formed by the combination of mercury with other metals. In the case of sodium amalgam, sodium is added to mercury. This mixture is an example of a liquid in solid solution.

Liquid in Solid Solution:
A liquid in solid solution is a type of solution where a liquid is dissolved in a solid. In this type of solution, the liquid is the solute and the solid is the solvent. The solute is completely dissolved in the solvent, forming a homogeneous mixture. Examples of liquid in solid solutions include:

- Amalgam of mercury with sodium
- Eutectic mixture of salt and ice
- Sugar solution in water
- Ethanol solution in water

Amalgam of Mercury with Sodium:
Mercury and sodium are two metals that are not soluble in each other in their pure forms. However, when they are combined in the presence of a small amount of water, they form an amalgam. The resulting mixture is a liquid in solid solution.

Uses of Amalgam of Mercury with Sodium:
Amalgam of mercury with sodium is used in various industrial applications. Some of the common uses are:

- Production of chlorine and sodium hydroxide in the chlor-alkali process
- Production of metallic sodium
- Extraction of gold and silver from their ores
- Dental fillings

Conclusion:
Amalgam of mercury with sodium is an example of a liquid in solid solution. It is a useful mixture used in various industrial applications.