A block of ice `-10^(@)C` is slowly heated and converted to steam at `100^(@)C`. Which of the following curves represent the phenomenon qualitatively?

Options

A.
B.
C.
D.

Answer

To analyze the heating process of a block of ice at -10°C being converted to steam at 100°C, we can break down the process into several steps and represent it qualitatively on a temperature vs. heat graph.

### Step-by-Step Solution:

1. **Initial State**: The block of ice starts at -10°C. At this stage, it is in solid form.

2. **Heating the Ice**: As heat is supplied, the temperature of the ice will increase from -10°C to 0°C. This is a linear increase in temperature as the ice absorbs heat.

3. **Phase Change (Melting)**: At 0°C, the ice begins to melt into water. During this phase change, the temperature remains constant at 0°C while the ice absorbs heat (latent heat of fusion). This heat is used to break the bonds between the ice molecules, allowing them to transition into the liquid state.

4. **Heating the Water**: Once all the ice has melted and we have water at 0°C, further heating will raise the temperature of the water from 0°C to 100°C. This again is a linear increase in temperature as the water absorbs heat.

5. **Phase Change (Vaporization)**: At 100°C, the water begins to convert into steam. Similar to the melting process, during this phase change, the temperature remains constant at 100°C while the water absorbs heat (latent heat of vaporization). This heat is used to convert the water into steam.

6. **Final State**: After all the water has been converted to steam, the temperature can increase further if more heat is supplied, but for this problem, we stop at the steam phase at 100°C.

### Qualitative Graph Representation:
- The graph will have a rising slope from -10°C to 0°C (heating the ice).
- A horizontal line at 0°C (melting the ice).
- Another rising slope from 0°C to 100°C (heating the water).
- A horizontal line at 100°C (vaporizing the water).
- The graph will illustrate the temperature changes and the constant temperature during phase changes.

### Conclusion:
The correct qualitative curve representing the phenomenon involves two linear segments (heating the ice and heating the water) and two horizontal segments (melting and vaporization).

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