`Au(s)hArrAu(l)` The formation of liquid is favoured at

Options

A. High pressure, low temperature
B. High pressure, high temperature
C. Low pressure, high temperature
D. Low pressure, low temperature

Explanation

To determine the conditions under which the formation of liquid gold (Au) is favored, we need to analyze the equilibrium between solid gold (Au(s)) and liquid gold (Au(l)).

### Step-by-Step Solution:

1. **Understanding the Phase Transition**:
- The equilibrium reaction is given as:
\[ \text{Au(s)} \rightleftharpoons \text{Au(l)} \]
- This represents the melting of solid gold into liquid gold.

2. **Volume Change During Melting**:
- When solid gold melts into liquid gold, the volume increases. This is a crucial point because it affects how pressure influences the equilibrium.

3. **Le Chatelier's Principle**:
- According to Le Chatelier's Principle, if a change is applied to a system at equilibrium, the system will adjust to counteract that change.
- Since the volume increases during the melting process, applying pressure will shift the equilibrium to the left (towards the solid), favoring solid gold.

4. **Effect of Pressure**:
- Therefore, to favor the formation of liquid gold, we need to apply low pressure. High pressure would not favor the melting process because it would push the equilibrium towards the solid phase.

5. **Endothermic Nature of Melting**:
- The melting of gold is an endothermic process, meaning it absorbs heat. For endothermic reactions, increasing the temperature favors the forward reaction (in this case, melting).
- Thus, a high temperature is also favorable for the formation of liquid gold.

6. **Conclusion**:
- Combining both effects, we conclude that the formation of liquid gold is favored at **low pressure and high temperature**.

### Final Answer:
The formation of liquid gold is favored at **low pressure and high temperature**.