Can equilibrium be achieved between water and its vapour in an open vassel ? Explain.

Answer

**Step-by-Step Solution:**

1. **Understanding Equilibrium**: Equilibrium in a chemical system occurs when two opposing processes happen at the same rate. In the case of water and its vapor, the two processes are evaporation (liquid to vapor) and condensation (vapor to liquid).

2. **Conditions for Equilibrium**: For equilibrium to be established between water and its vapor, the rate of evaporation must equal the rate of condensation. This means that the amount of water evaporating must be equal to the amount of vapor condensing back into liquid.

3. **Open Vessel Scenario**: In an open vessel, water can evaporate freely into the air. However, since the vessel is open, the vapor that forms can escape into the atmosphere.

4. **Lack of Condensation**: In an open vessel, there is no mechanism for the vapor to condense back into liquid water because the vapor can escape. Therefore, the rate of condensation is effectively zero.

5. **Conclusion**: Since the rate of evaporation will not be balanced by the rate of condensation in an open vessel, equilibrium cannot be achieved. Over time, all the water will eventually evaporate, leaving the vessel dry.

**Final Answer**: Equilibrium cannot be achieved between water and its vapor in an open vessel because the vapor escapes and there is no condensation occurring to balance the evaporation.

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