Dissolving sodium chloride in water will
1: raise the freezing point of the solution, 2. raise the freezing point of the sodium chloride, 3. lower the freezing point of the solution, or 4. lower the freezing point of the sodium chloride?
Read this and decide for yourself:
http://en.wikipedia.org/wiki/Freezing-point_depression
When sodium chloride (NaCl) is dissolved in water, it forms sodium ions (Na⁺) and chloride ions (Cl⁻). The interaction between these ions and water molecules disrupts the crystal structure of pure water, leading to changes in its freezing point.
The presence of sodium chloride in water will actually lower the freezing point of the solution, rather than affecting the freezing point of the sodium chloride itself. This phenomenon is known as freezing point depression.
To understand why this happens, we need to consider the concept of freezing point and how it is affected by the presence of solutes. The freezing point of a liquid is the temperature at which it transitions from a liquid phase to a solid phase (freezes). In pure water, this occurs at 0 degrees Celsius (32 degrees Fahrenheit) under standard conditions.
When a solute such as sodium chloride is added to water, it interrupts the formation of ice crystals by getting in the way of the water molecules as they try to arrange themselves in a regular lattice structure during freezing. This interference prevents the water from solidifying efficiently, thus lowering the freezing point.
The extent of freezing point depression depends on the concentration of the solute. In the case of sodium chloride, the more salt is dissolved in water, the lower the freezing point of the solution will be. This property has practical applications, such as in the use of salt to de-ice roads during winter, as it helps to prevent water from freezing at lower temperatures.
In summary, dissolving sodium chloride in water will lower the freezing point of the resulting solution rather than affecting the freezing point of the sodium chloride itself.