Why does salt melt ice?
Show answer & explanation
Answer: It lowers freezing point
It generates heat — Wrong. Salt doesn't generate heat. The melting process actually absorbs heat from surroundings, making it colder. Salt works through a different mechanism - changing the freezing point of water.
It lowers freezing point ✓ — Correct! Salt lowers water's freezing point through 'freezing point depression'. Pure water freezes at 0°C, but salt water can stay liquid below 0°C. When salt dissolves, it interferes with water molecules forming ice crystals. This forces existing ice to melt even in cold temperatures. That's why we salt roads in winter!
It breaks ice crystals — Wrong. Salt doesn't physically break ice crystals. It works at the molecular level by interfering with how water molecules bond together to form ice. The process is chemical, not mechanical.