Why NaCl solution freeze at lower temperature?
Answers
Answer:
because it's freezing point is lower
Answer:
When NaCl is added to water the vapor pressure of water over NaCl solution decreases. This vapour pressure in order to become equal with the pressure of the outside atmosphere (for boiling of NaCl solution) thus needs more heating. Hence boiling point elevates and becomes more.
Again, presence of Na+ and Cl- ions in water interferes while freezing the water to make ice. To overcome this interference the solution needs cooling to a temperature lower than the freezing point of water. Remember, it's easier to freeze a pure solvent than to freeze when a solute is dissolved in it because accommodation of Na+ and Cl- in ice cages requires lesser degree of freedom of ions to trap them in ice cages. Therefore the solution needs additional cooling.