Question

Which of the following have a definite shape and volume?

Answer 1

Hint: The three states of matter namely, solid, liquid and gas have different physical properties due to difference in their force of attraction between two atoms. In solids the force of attraction between the constituent atoms is very strong. On the other hand, gases have a weak force of attraction. Liquids lie in between the two states of matter in terms of force of attraction.

Complete answer:
In a solid, the particles are packed closely together in a lattice. The particles are not free to move about within the substance. Molecular motion for the particles in a solid is confined to vibrations about their fixed position only. Hence Solids have a fixed shape that requires a lot of force to change. Solids have a definite volume i.e. their size remains the same irrespective of where they are placed.
Liquids are nearly incompressible fluids that conforms to the shape of the container into which it is poured keeping its total volume constant. The volume of liquid remains the same irrespective of the pressure. However, liquids do not have a fixed shape.
Gas is one of the fundamental states of matter. Gases can be compressed when pressure is applied. So, they do not have a definite volume. Gases diffuse into air and the size of gas cannot be determined as a constant. Hence, they do not have a fixed shape as well.
We can conclude that solids have fixed shape and volume.

Therefore, the correct answer is option (A).

Note:
Along with the three states of matter, there is one more state of matter known as plasma. Plasma is considered as a subset of gases however the two states of matter are not the same. In plasma, the atoms are stripped away of their electrons and the charged particles like electrons, nuclei roam freely.