Final answer:
Specific gravity is defined as the weight of a liquid compared to that of distilled water, with pure water at 4°C having a specific gravity of 1.0. The correct option is a.
Step-by-step explanation:
The term you are looking for is specific gravity. It is defined as the weight of a liquid compared to that of an equal volume of distilled water. Specifically, specific gravity is a dimensionless ratio that compares the density of a substance to that of a reference substance, typically at the same temperature and pressure conditions.
By convention, the reference substance is often pure water at 4 degrees Celsius, which has a specific gravity of 1.0.
Since distilled water is assigned a specific gravity of 1.0, any solute added to the water will increase its specific gravity. Thus, if a liquid's specific gravity is greater than 1, it means that the liquid is denser than distilled water, and conversely, if it is less than 1, the liquid is less dense. The correct option is a.