Question

A gas has ________.
(A) definite volume and no definite shape
(B) definite shape and no definite volume
(C) definite shape and definite volume
(D) no definite shape and no definite volume.

Answer 1

In order to this question, to know the correct option related to the shape and the volume of a gas, we will go through the physical properties of the gas to know about the shape and volume of the gas. Then we will discuss more about the gas.

Complete step-by-step solution:
A gas has no definite shape and no definite volume. It takes the shape of the container in which it is placed. It is due to the weak intermolecular forces of attraction between the gas molecules.
A gas has been established that molecules have sizes on the order of a few angstrom units $1\mathop A\limits^{^\circ } = {10^{ - 8}}cm$ and that there are about $6 \times {\text{1}}{0^{23}}$ molecules in one mole, which is defined as the amount of a substance whose mass in grams is equal to its molecular weight.
Gas, one of the three fundamental states of matter, with distinctly different properties from the liquid and solid states.
Gases have a unique property in that they tend to have no structure at all. They have neither a definite size nor a definite shape, while ordinary solids have both and liquids have a definite size, or volume, even though they conform their shape to that of the container in which they are put.
On a molecular level, gases do have a structure of some kind. They are made up of a large number of molecules moving in a chaotic manner in all directions, colliding with one another and the container's walls. Beyond that, there is no structure—the molecules are dispersed in space simply at random, moving in arbitrary directions at speeds that are dispersed uniformly around an average determined by the gas temperature.
Hence, the correct option is (D) no definite shape and no definite volume.

Note: Gases are treated as a vast number of tiny particles that are subject to physics' laws. The kinetic theory of gases may describe their properties, which are mainly due to the motion of the molecules.