During melting, density decreases as mass remains constant. What happens to the volume?

• A. Volume increases
• B. Volume decreases
• C. Volume stays the same
• D. Volume becomes zero

Answer: (A)

When mass stays the same, density and volume move inversely: density = mass/volume. If the density decreases while the mass is constant, the volume must increase.

During melting, particles gain energy and spread apart, so the substance takes up more space. Since the amount of matter hasn’t changed, the larger space means a larger volume, and the density drops accordingly. For a quick sense, if density falls from 2 g/cm^3 to 1 g/cm^3 for the same mass, the volume doubles, showing the volume increases as density decreases.

Volume staying the same would require density to stay the same, which it does not. Volume decreasing would imply density increasing, which contradicts the given change. Volume becoming zero isn’t possible with a finite mass.