8.2 Freezing and melting go on at the same time Hydrogen bonds form during freezing of water, releasing heat They break during melting, absorbing heat Adding salt to water decreases the melting point of water Aqueous solution of Nacl Fiqure 8.9 (a)In a mixture of ice and liquid water at oC, the number of H2O molecules entering the solid phase is equal to the number of H2o molecules entering the liquid phase. (b) Adding a solute such as sodium chloride, decreases the number of H2O molecules entering the solid phase because now there are fewer liquid H2o molecules at the interface.8.2 Freezing and melting go on at the same time Hydrogen bonds form during freezing of water, releasing heat. They break during melting, absorbing heat. Adding salt to water decreases the melting point of water