Hi,
I used to be a student in prep school in France (PC* for those who know), it was more than 10 years ago... I'm not working in the domain of chemistry at all but today, while I was cleaning up some old stuff, I came across the subject of a practical exam I had taken (for the Ecole Polytechnique, probably the most renown school in France - I didn't pass, unfortunately
). I remember that I did not do very well, maybe someone will provide me with an answer today...
The objective was to find 4 components: A, B, C, D, that would respect the following rules:
A+B --> précipité 1 (solid)
C+B --> stay liquid, no color change, no gaz emission
A+D --> précipité 2 (solid)
C+D --> an irritating gaz
It was possible to use other standard components as well, heat the mixture or stir it. Of course, the 4th reaction was to remain theoretical
. There are several answers possible, but the objective was to find one that could be illustrated with components that can be commonly found in a lab.
Will someone be able to provide an answer to this ten years old puzzle?
LeNours