Does salt or sugar lower the freezing point of water?

Answer 1

Pure water freezes at 0 degrees Celsius. When other things are put into solution in water, it normally causes the temperature of freezing to lower. Salt is capable of causing ice to melt because the it lowers the freezing point of any water (including ice) with which it is in contact, and that is why it is used on icy roads.

So the short answer is, when there is salt or sugar in water, you have to remove more heat to freeze it, and so it takes longer.

Answer 2

yes salt does lower the freezing point of water When salt (NaCl) dissolves in water, its sodium (Na+) and chlorine (Cl-) ions leave the salt crystals and mix separately among the water molecules. These ions affect the water molecules and their freezing and boiling temperatures in different ways:

1. Lower freezing point

Water molecules form crystals when freezing. Na+ and Cl- ions from the salt get in the way of the water molecules, making it harder for them to become re-arranged into crystals. This means that salt water remains in a liquid state for longer as the temperature reduces.

2. Higher boiling point

The answer to the question why do bubbles form when water is boiled? explains how, as the temperature of water rises, its molecules move around faster, collide more often and release more water vapor gas molecules. When the temperature reaches boiling point - about 100°C (212°F) - the pressure from the release of these molecules (the vapor pressure) becomes greater than atmospheric pressure and water vapor starts to escape as bubbles.

In salty water, Na+ and Cl- ions occupy some of the space between the water molecules. As temperature increases, although the water molecules are moving faster, there are less of them, so there are fewer collisions, less release of water vapor molecules and lower vapor pressure compared to pure water at the same temperature. It takes more energy (temperature) for the vapor pressure of salt water to reach and exceed atmospheric pressure and start to boil.

To raise the boiling point of one liter (34 ounces) of water by 1°C (1.8°F) requires about 58 grams (2 ounces) of salt. This is much more that the amount of salt typically added to boiling vegetables, which is done primarily for taste.

Answer 3

water freezes at normal pressure at zero centigrade. temperature is a measure of the kinetic energy of the molecules. For water, at that low energy, the molecules slow down enough that the intermolecular attractions between the negative side of the molecule (oxygen) makes a weak bond to the positively charged sides (hydrogen) of other nearby molecules. The molecules lock up into a hexagonal pattern in three dimensions, forming the matrix of the solid ice. if the water has sugar dissolved (or anything dissolved) these other molecules get in the way of these weak bonds (hydrogen bonds) and in order to freeze solid, it takes a lower energy for the molecules to slow down even more, to the point that these molecules can be bonded around, letting water get solid. the more dissolved into the water, the lower the temperature required to freeze.

Answer 4

No, freezing point depression is a colligative property and thus depends only on the number of (non-volatile) species in solution. Sugar does not dissociate in water, but salt dissociates into ions (sodium and chloride ions in the case of table salt). In the NaCl case, the salt produces double the freezing point depression compared to sugar on a molar basis.

Answer 5

Salt lowers the freezing point of water, while sugar does not have the same effect. When salt is added to water, it disrupts the hydrogen bonding between water molecules, making it more difficult for them to form solid ice crystals and therefore lowering the freezing point of the solution.

Answer 6

it does not increase the freezing point of water in any way.

Answer 7

Salt affects the freezing point of water by preventing ice crystals from forming. It also increases the temperature water can be boiled at.

Sugar does not have the same properties.