why nacl solution freez at lower temperature but water boil at high temperature.
Answers
Freezing point depends upon the attraction between the molecules (intermolecular attraction) of the liquid. When salt (NaCl) is added to water,it decreases the intermolecular attraction as it creates attractions between water molecules & Na+ or Cl− ions. Thus the freezing point decreases after adding salt.
Boiling point depends upon the vapour pressure of the liquid. After addition of salt, the salt ions on the liquid surface prevent water molecules from escaping to the atmosphere, thus reducing the vapour pressure. Thus the boiling point elevates after adding salt.
When non volatile solids are added eg-nacl to water. Boiling point increases and melting point decreases. It is because the number of water molecules available to become vapourise/freeze decreases due to impurity. ... As a result, the solution freezes at a lower temperature and boils at a higher temperature.