Densities of diamond and graphite are 3.5 and 2.5 gm/ml. `C_("daimond") hArr C_("graphite") , Delta_(t) ` H = -1.9 KJ/ mole favourable conditions for formation of diamond are

Options

A. high pressure and low temperature
B. low pressure and high temperature
C. high pressure and high temperature
D. low pressure and low temperature

Answer

To determine the favorable conditions for the formation of diamond from graphite, we need to analyze the given information and apply the principles of thermodynamics and physical chemistry.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
The reaction we are considering is:
\[ \text{C (diamond)} \rightleftharpoons \text{C (graphite)} \]
The enthalpy change (\(\Delta H\)) for this reaction is given as \(-1.9 \, \text{kJ/mol}\). This indicates that the conversion of diamond to graphite is exothermic.

2. **Analyzing the Densities**:
The densities of diamond and graphite are provided:
- Density of diamond = 3.5 g/mL
- Density of graphite = 2.5 g/mL

Since diamond has a higher density than graphite, it occupies less volume for the same mass.

3. **Applying Le Chatelier's Principle**:
According to Le Chatelier's principle, if a system at equilibrium is subjected to a change in pressure or temperature, the system will adjust to counteract that change.

- **Effect of Pressure**: Increasing the pressure favors the side of the reaction that has a smaller volume. Since diamond has a higher density (and thus occupies less volume), increasing pressure will favor the formation of diamond from graphite.

4. **Effect of Temperature**:
The reaction is endothermic in the reverse direction (from graphite to diamond). According to the principles of thermodynamics:
- For an endothermic reaction, increasing the temperature favors the formation of products. Therefore, high temperatures will also favor the conversion of graphite to diamond.

5. **Conclusion**:
From the above analysis, we conclude that both high pressure and high temperature favor the formation of diamond from graphite.

### Final Answer:
The favorable conditions for the formation of diamond from graphite are **high pressure and high temperature**.

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