Answer to Question #207992 in General Chemistry for ARKHYE

Question

Inquiry in Action:

1. People who live in colder climates have seen the trucks put or sprinkle salt on the roads when snow or ice is forecast. Why do they do that?

2. When planes fly in cold weather, the planes need to be de-iced before liftoff. Why is that done?

Answer 1

1.Salt causes a phenomenon called freezing point depression, which means it lowers the freezing point of water. Water normally freezes at 32 degrees Fahrenheit, but when you add salt, that threshold can drop as low as 20 degrees Fahrenheit.

2.When ice builds up along the leading edges of the wings it changes their shape – and thus their ability to generate lift. Aircraft are fitted with de-icing systems, but in severe conditions even these can be inadequate, requiring the application of high-pressure blasts of antifreeze.