The graph shows what happens when a mixture of ice and water is heated continuously. The temperature of the mixture remains constant (0°C) till all the ice melts as shown by the line AB. This temperature is the melting point of ice. On further heating, the temperature rises steadily from 0°C to 100°C as shown by the line BC, At 100°C water starts converting into steam. This temperature is the boiling point of water. Further heating does not change the temperature and the conversion waters steam continues as shown by the line CD.
