Adding a solute to a solvent (salt into water for example) disrupts the intermolecular bonds in the otherwise homogeneous fluid. The new solution will have a lower freezing po … int and higher boiling point as a result. Salt is often added to ice baths to reduce the temperature as well as adding salt to ice to melt it.
http://www.answers.com/Q/When_a_Solute_is_added_to_a_solvent_the_freezing_point_of_the_solution_is
Because changes in the boiling point of the solvent (T BP) that occur when a solute is added to a solvent result from changes in the vapor pressure of the solvent, the magnitude of the change in the boiling point is also proportional to the mole fraction of the solute.
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch15/colligative.php
Because the change in vapor pressure is a colligative property, which depends only on the relative number of solute and solvent particles, the changes in the boiling point and the melting point of the solvent are also colligative properties.
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch15/colligative.php
The boiling point rises and the freezing point lowers. The reason being, when a solute dissolves in a solvent, the solute molecules wedge themselves between the solvent molecu … les. In order for the solvent to freeze, its molecules have to get close enough together to form a solid.
http://www.answers.com/Q/When_a_Solute_is_added_to_a_solvent_the_freezing_point_of_the_solution_is
P = vapor pressure of the pure liquid, or solvent. P = vapor pressure of the solvent in a solution. When the temperature of a liquid is below its boiling point, we can assume that the only molecules that can escape from the liquid to form a gas are those that lie near the surface of the liquid.
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch15/colligative.php
By definition, one of the properties of a solution is a colligative property if it depends only on the ratio of the number of particles of solute and solvent in the solution, not the identity of the solute. Very few of the physical properties of a solution are colligative properties.
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch15/colligative.php
A non-volatile solute has a vapor pressure of zero, so the vapor pressure of the solution is less than the vapor pressure of the solvent. Thus, a higher temperature is needed for the vapor pressure to reach the surrounding pressure, and the boiling point is elevated.
https://en.wikipedia.org/wiki/Boiling-point_elevation
A solution of 76.7% water and 23.3% salt will freeze at -21.1 degrees Celsius, which is why adding salt to ice will melt it when the temperature is below freezing. The boiling point increases by the same principle of disturbing the homogeneous fluid.
http://www.answers.com/Q/When_a_Solute_is_added_to_a_solvent_the_freezing_point_of_the_solution_is
The same sort of thing happens when trying to boil the solvent, only instead of holding the solvent molecules apart, the solute molecules end up holding them together, preventing them from boiling. Therefore, a more energy is needed to break the bond between solvent and solute, which allows the solvent to boil.
http://www.answers.com/Q/When_a_Solute_is_added_to_a_solvent_the_freezing_point_of_the_solution_is
The change in the vapor pressure that occurs when a solute is added to a solvent is therefore a colligative property. If it depends on the mole fraction of the solute, then it must depend on the ratio of the number of particles of solute to solvent in the solution but not the identity of the solute.
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch15/colligative.php
what happens to the boiling point when a solute is added to a solution
When a solute is added to a solution, the magnitude of the change in the boiling point is also proportional to the mole fraction of the solute. When a solute is added to a solution, the magnitude of the boiling point will change.