This is a diagram showing the process of distillation of salt water into pure water. where is the pure water in the diagram?

Distillation is the process of separating a mixture of liquids, or a mixture of solid (dissolved salt in this case) and a liquid (water), advantage taken of the difference in boiling points of the ingredients.

In the diagram, the salt water is placed in flask A and heated using a gas (or Bunsen) burner.  Water is converted to steam and passes through the fractionating column B, which is normally required only for separating two liquids of close boiling points.  The vapour is then passed through the condenser (or Liebig condenser as some are called) C which condenses the water vapour back into liquid form.  Note that the cooling water enters at the bottom and leaves the conderser from the top, according to the counter-current principle.  The condensed liquid, pure water in this case, will then drip down into the conical flask D on the right.