Why does salt melt ice on sidewalks?

Answer: Salt lowers water's freezing point

Salt generates chemical heat — Wrong. Salt dissolving is actually endothermic (absorbs slight heat). It works by changing ice's melting point, not by generating warmth.

Salt makes ice too slippery to stick — Wrong. Slipperiness doesn't make ice melt. Salt works by chemically lowering water's freezing point, causing ice to turn to liquid.

Salt lowers water's freezing point ✓ — Correct! When salt dissolves in the thin water layer on ice, it creates saltwater, which freezes at lower temperature than pure water (-21°C vs 0°C). This makes ice melt even in freezing weather. It's 'freezing point depression'!