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https://www.chemguide.co.uk/physical/phaseeqia/idealpd.html#top

I learned about phase diagrams involving partial Vapour composition, temperature and composition of binary solutions from this website. You can find it if you scroll down to a little above the end

First it considers a binary solution of volatile liquids. The diagram involves boiling point on Y-axis and concentration of one component on X-axis varying from 100 to 0 % (and hence 0 to 100% for other component). As composition changes, so does the boiling point of the mixture. We obtain a smooth blue curve. If we consider any point on the curve and draw a horizontal line then it will intersect a pink curve and we will consider the X-coordinate of the point of intersection which will give the composition of the vapours above the liquid developed when the liquid is at its boiling point.

I don't understand that when we take the liquid at its boiling point, it forms an equilibrium with its vapour phase whose composition is given by the pink curve in the diagram. However the amount of vapour depends on how much energy is provided to the liquid as latent heat of vaporisation. If I provide sufficient heat to liquid then all of it will convert to vapour at constant temperature(boiling point), in that case the composition of the vapours will be same as liquid (but the composition of vapours is always different from that of liquid from the diagram). This implies that the composition of vapours should depend on how much of liquid vaporises, which is never considered. Is it possible that only when all the liquid is vaporised, only then the vapour composition is equal to that of liquid and that it is given by the diagram for the rest of the cases.

Please clarify if there's a misunderstanding.

I learned about phase diagrams involving partial Vapour composition, temperature and composition of binary solutions from this website. You can find it if you scroll down to a little above the end

First it considers a binary solution of volatile liquids. The diagram involves boiling point on Y-axis and concentration of one component on X-axis varying from 100 to 0 % (and hence 0 to 100% for other component). As composition changes, so does the boiling point of the mixture. We obtain a smooth blue curve. If we consider any point on the curve and draw a horizontal line then it will intersect a pink curve and we will consider the X-coordinate of the point of intersection which will give the composition of the vapours above the liquid developed when the liquid is at its boiling point.

I don't understand that when we take the liquid at its boiling point, it forms an equilibrium with its vapour phase whose composition is given by the pink curve in the diagram. However the amount of vapour depends on how much energy is provided to the liquid as latent heat of vaporisation. If I provide sufficient heat to liquid then all of it will convert to vapour at constant temperature(boiling point), in that case the composition of the vapours will be same as liquid (but the composition of vapours is always different from that of liquid from the diagram). This implies that the composition of vapours should depend on how much of liquid vaporises, which is never considered. Is it possible that only when all the liquid is vaporised, only then the vapour composition is equal to that of liquid and that it is given by the diagram for the rest of the cases.

Please clarify if there's a misunderstanding.

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