Salt does not stop melting ice at a specific temperature. Instead, salt lowers the freezing point of water, making it melt at a lower temperature than it would without salt.
Here's why:
- Salt dissolves in water, forming a salt solution.
- Salt solutions have a lower freezing point than pure water. This means that the salt solution will remain liquid at temperatures below 0°C (32°F), the freezing point of pure water.
- The amount of salt added determines how much the freezing point is lowered. More salt lowers the freezing point further.
Practical Applications:
Salt is used to melt ice on roads and sidewalks because it lowers the freezing point of water, preventing ice from forming or melting existing ice.
Examples:
- Pure water freezes at 0°C (32°F).
- A solution of 10% salt by weight will freeze at about -6°C (21°F).
Important Note: Salt does not melt ice; it simply lowers the temperature at which water freezes. The ice still melts due to heat energy from the environment.
