Chemistry · EQUILIBRIUM

A sealed container at a constant temperature contains water and its vapour at equilibrium. If the volume of the container is suddenly doubled at the same temperature, which of the following correctly describes the instantaneous relationship between the rate of evaporation (\( r_{\text{evap}} \)) and the rate of condensation (\( r_{\text{cond}} \)), and the final equilibrium vapour pressure compared to the initial vapour pressure \( P_0 \)?

1. Initially \( r_{\text{evap}} > r_{\text{cond}} \); final vapour pressure is \( 0.5 P_0 \)
2. Initially \( r_{\text{evap}} < r_{\text{cond}} \); final vapour pressure is \( 0.5 P_0 \)
3. Initially \( r_{\text{evap}} = r_{\text{cond}} \); final vapour pressure is \( 2 P_0 \)
4. Initially \( r_{\text{evap}} > r_{\text{cond}} \); final vapour pressure is equal to \( P_0 \)