What happens to temperature during the melting of ice?

• A. Temperature remains constant at the melting point during melting.
• B. Temperature rises above the melting point before melting begins.
• C. Temperature drops below freezing during melting.
• D. Temperature never changes.

Answer: (B)

During a phase change from solid to liquid at a fixed pressure, the heat added goes into breaking the solid’s lattice rather than raising temperature. For ice melting at 1 atm, the temperature stays at 0°C while melting because that energy (the latent heat of fusion) is used to convert ice into liquid water. Only after all the ice has melted does further heating raise the temperature of the liquid. So the correct idea is that the temperature remains constant at the melting point during the melting process.