I was reading about Andrew's isotherms and about the continuity of state.
What confused me was the continuous conversion of gaseous state to liquid state.
Now my textbook says that by keeping volume constant and increasing pressure and then keeping pressure constant and letting the gas cool we are able to convert the substance from gaseous to liquid state.
Now what confused me is this sentence in my textbook - "Thus in the absence of the surface of discontinuity, there is no way of distinguishing between liquid and gas".
What does this mean?
Also, how is this conversion continuous, as along line LD wouldn't the gas convert to liquid in such a way that both states coexist? How is it possible that this conversion is continuous?