Which state of matter has a definite volume and a definite shape?

• A. Gas
• B. Liquid
• C. Solid
• D. Plasma

Answer: (C)

Definite shape and volume come from how the particles are arranged and held together. In a solid, particles are tightly packed and bound by strong forces, so they stay in fixed positions and the structure keeps its own shape. That same rigidity means the volume doesn’t change, even if the surroundings change. By contrast, liquids have a definite volume but take the shape of their container because their particles can slide past one another. Gases spread to fill both the space and the container, so they have neither a fixed shape nor a fixed volume, and plasmas behave similarly to highly energized gases. So, the state that has both a definite shape and a definite volume is the solid.