Substance P at `-80^(@)`C has definite volume but no definite shape and possess fluidity. At `-55^(@)`C, substance P neither has definite volume nor definite shape. Which of the following could be the melting and boiling points of substance P?

Options

A. `{:("Melting point","Boiling point"),(-92^(@)C,-60^(@)C):}`
B. `{:("Melting point","Boiling point"),(-85^(@)C,-40^(@)C):}`
C. `{:("Melting point","Boiling point"),(-80^(@)C,-56^(@)C):}`
D. `{:("Melting point","Boiling point"),(-70^(@)C,-50^(@)C):}`

Answer

To determine the melting and boiling points of substance P based on the information provided, we can analyze the conditions at which it exists in different states of matter.

### Step-by-Step Solution:

1. **Understanding the States of Matter**:
- At `-80°C`, substance P has a definite volume but no definite shape, which indicates that it is in a **solid state**. Solids have a fixed volume and shape.
- At `-55°C`, substance P has neither a definite volume nor a definite shape, indicating that it is in a **liquid state**. Liquids have a fixed volume but take the shape of their container.

2. **Identifying Melting Point**:
- The melting point is the temperature at which a solid turns into a liquid. Since substance P is solid at `-80°C` and becomes liquid at `-55°C`, we can conclude that the melting point of substance P is somewhere between these two temperatures.
- Therefore, the melting point of substance P is **greater than `-80°C` and less than or equal to `-55°C`**.

3. **Identifying Boiling Point**:
- The boiling point is the temperature at which a liquid turns into a gas. Since substance P is liquid at `-55°C`, it will remain a liquid until it reaches its boiling point. The boiling point must be above `-55°C`.
- Therefore, the boiling point of substance P is **greater than `-55°C`**.

4. **Conclusion**:
- Based on the analysis, we can summarize that:
- The melting point of substance P is between `-80°C` and `-55°C`.
- The boiling point of substance P is greater than `-55°C`.

### Final Answer:
- The melting point of substance P could be any value between `-80°C` and `-55°C`.
- The boiling point of substance P could be any value greater than `-55°C`.