Final answer:
The statement that must be true if an object floats in water is that the object is less dense than water. This allows the object to be buoyed by the water, making it float irrespective of other properties like solubility or surface area.
Step-by-step explanation:
When considering the question, If an object floats in water, which statement must be true? the correct answer is B. The object is less dense than water. An object's ability to float is determined by its density relative to the density of the fluid in which it is placed. Objects that are less dense than water will float because the water provides a buoyant force that is greater than the weight of the object. This principle is applicable to all fluids, not just water. For example, ice with a relative density of about 0.91, which is less than 1, floats on water. Important to note is that solubility and surface area do not directly influence an object's buoyancy in this context. Factors such as whether the object can covalently bond to water molecules or how well it dissolves are unrelated to the object's ability to float. When an object floats in water, it indicates that the object is less dense than water. Buoyancy, which is the upward force exerted by a fluid (in this case, water), opposes the weight of the object. For an object to float, the buoyant force must be equal to or greater than the weight of the object. This implies that the object displaces its own weight of water, and therefore, the object is less dense than the water it displaces.