Which salt is commonly used to melt ice on roads?

The correct answer is Calcium chloride. Calcium chloride (CaCl₂) is widely used for de-icing roads because it effectively lowers the freezing point of water, preventing ice formation and melting existing ice. It also releases heat when dissolved (exothermic reaction), which aids in the melting process and allows it to work at lower temperatures than other salts like sodium chloride.

• Potassium nitrate is primarily used in fertilizers and explosives, not as a de-icer.
• Ammonium nitrate is also a fertilizer and can be explosive, making it unsuitable for road de-icing.
• Potassium chloride can be used for de-icing but is generally less effective and more expensive than calcium chloride or sodium chloride, especially at very low temperatures.