I have quite an unclear understanding of relative humidity. I am writing my understanding on the topic and please correct me wherever I'm wrong:
What I understood:
Let's say $\ce{H2O}$ has a (saturated) vapour pressure of $x~\pu{atm}$ at a certain temperature. Now, relative humidity (RH) is the ratio of the partial pressure of water vapour to the equilibrium vapour pressure of water at a given temperature.
So what this means is that if RH = 100% then the maximum amount of water vapours is present in the air. Now if RH = 50% means that the amount of water vapours present in the air is only half of the maximum possible.
- So, does this mean the water has not been fully evaporated up to the limit it can?
- Does this mean that the equilibrium has not yet been established, and the reaction tends to shift in the forward direction? If yes, then what is stopping the reaction to move forward?
- Does 100% RH mean the water and it's vapour are in equilibrium?
Can relative humidity be compared with an example of a sponge? There's a limit of the amount of water a sponge can absorb water. If it has only absorbed 50% means there is still room for more absorption until 100% capacity is reached.