Refer to the plot of temperature versus time (figure) showing the changes in the state of ice on heating (not to scale).

(a) The region AB represents the ice and water in thermal equilibrium.

(b) At B, the water starts boiling.

(c) At C, all the water gets converted into steam.

(d) C to D represents water and steam in equilibrium at boiling point.

Choose the correct alterative/s:

1.  (b, c)

2.  (a, d)

3.  (c, d)

4.  (b, d)

(2) Hint: Use the concept of state change.
Step 1: Find the different type of stages in the state change of water.
During the process AB, the temperature of the system is 0°C. Hence, it represents the phase change that is the transformation of ice into the water while the temperature remains 0°C.
BC represents the rise in temperature of water from 0°C to 100°C (at C). Now, the water starts converting into steam which is represented by CD.