why does adding NaCl to ice make it colder?

Question

when making icecream you add nacl to ice to "make it colder"

Answer 1

Salt does not make the ice colder. It does make water that is in with the ice colder. Any impurity lowers the melting point of water to a certain degree. Adding salt allows water to exist at a temperature lower than 32F which is it's normal freezing point. This is the same principle involved in spreading salt on icy or snow covered roads. It lowers the freezing point of water to a temperature lower than the air temperature and the ice melts.

Answer 2

Salt lowers the temperature at which water freezes.

Therefore, saltwater ice can be colder than water ice and the icecream will freeze more quickly.

This is the same reason that salt is put on the roads in winter - it lowers the freezing point temperature and ice is less likely to form on the roads.

Answer 3

This is known as a colligative property. Whenever something is dissolved in a liquid, the dissolved particles disrupt the freezing process where they liquid molecules start to lock in place as they freeze. This added disruption lowers the freezing point a couple degrees depending on the liquid and how much is dissolved.

In the case of ice cream, the ice from the freezer is colder than the freezing point. Adding the salt causes the freezing point to lower a couple degrees than plain water so the salt-ice water solution surrounding the ice cream container is actually below the freezing point. This allows the ice cream to start freezing itself. Once

Answer 4

Dissolving anything takes heat. When heat is removed, it makes it colder. Adding salt to ice doesn't have much to do with making the ice colder. The ice is already colder than 32°F. The salt actually lowers the freezing temperature of the water so that the water can be liquid and still be below 32°F. Liquid water makes more contact with the ice cream container, making it freeze quicker.

Answer 5

Although dissolving NaCl is endothermic as you state the amount of head absorbed is very small - you would need a large amount of salt to give measurable effects - far more than needed for the mixture of ice and water. Adding salt to water does lower its freezing point, but the key thing is the ice in the water, not the water itself. Salt lowers the melting point of ice - so it melts quicker and absorbs heat till the new lower temperature is reached. Since adding salt to a mixture of ice and water lowers the temperature below 0 C the beer cools faster.

Answer 6

Ice from pure water melts at 0C, this means that the lowest temperature that ice can cool something down to would be 0C (more usually around 4C). Adding salt to ice lowers the melting point. This means that melted ice is at a lower temperature and allows you to cool things to a lower tempereture. This temperature depends on the type of salt used and the ratio of salt to ice.

Answer 7

Adding salt lowers the "freezing point" of water. So it "allows the mixture to be colder". Adding solute just changes the freezing points and boiling points of solvents. Which is why you add salt to ice cream, or add salt when boiling pasta, to make the temperature hotter.

Answer 8

The presence of any impurities will lower the freezing point of water.

Hence the addition of NaCl (an impurity), will lower the freezing point and hence your fridge will work have to lower its temperature so as to freeze the "impure" ice cream.

Answer 9

No... It has no effect at it's chemical property, but rather, salt has some "insulating" property when use in Ice cream.

Answer 10

Thanks it make my knowledge clear about NaCl and ice mixture.