chornedsnorkack - 16-2-2012 at 13:19
What can be predicted about vapour composition from the fact that the components form a higher boiling point azeotrope?
Like water and any strong acids or bases.
The mixture with azeotropic composition should emit vapour of the same composition, right?
And therefore, in a dilute aqueous solution, the concentration (mole or weight, values differ but conclusion is the same) of the solute in vapour
should be lower than the concentration of the solute in liquid.
Now apply this expectation on ammonia. Example 1M.
1,7 %. Fairly dilute.
Water is 55M. Lowered by ammonia, slightly.
So, 1,8% mole fraction of ammonia.
At 25 C, the vapour pressure of pure water is 32 mbar. Ammonia lowers it.
What should be the ammonia pressure over 1M ammonia at 25 C?