Question

The property to flow is unique to fluids. Which one of the following statements is correct?
A. Only liquids are fluids
B. Gases and solids behave like fluids
C. Gases and liquids behave like fluids
D. Only gases behave like fluids

Answer 1

Hint: The property to flow can be defined by the states of matter in which the molecules are loosely packed. More space proves the chances of flow of the elements in that specific state of matter, proving the state to be that of a fluid.

Complete answer:
Based on the states of matter in which the elements or the compounds exist, there are three specific states which are solid, liquid and gas.
Solids are more rigid structures because the molecules in a solid matter are arranged very closely. This close packing means that there is very low intermolecular space in the molecules that form the solid structure. This means that the molecules are not able to move freely.
In the case of liquids, the molecules are loosely packed as compared to solids. There is a visible nature of flow which is possible in case of liquid due to the presence of spaces between the molecules. Hence the molecules can in those spaces easily facilitating the flow of molecules of the liquid.
In the case of gases, the molecules attain a free state which means that the space between the molecules is very high. Therefore, it is the easiest for the gas molecules to flow as it occurs in the atmosphere.
Hence in both the cases of liquid and gas, the chances of flow of the liquids and gases is higher. Hence the fluid nature is present in liquids and gases only among the three states of matter.

Hence, the correct option is C. Gases and liquids behave like fluids.

Note:
Free space is very important for the movement of the molecules. In the presence of abundant free space, the molecules move in a zig-zag motion. This specific motion is known as Brownian motion.