Question

experiment of Anhydrous CrCl₃ synthesis from chromium (III) oxide via Ammonium Dichromate :

1. Why is an N₂ atmosphere maintained in the reaction tube?

2. Explain in terms of their structures why CrCl₃*6H₂O (i.e., [trans-CrCl₂(OH₂)₄]Cl*2H₂O) is soluble in water but CrCl₃ is not.

Answer 1

The trans complex of Chromium contains four molecules of water inside the coordination sphere and two water molecules outside the coordination sphere. So it is hydrated isomer or solvated isomer which is very similar to ionic isomers. Such isomers are soluble in water. But Cr Cl3 do not have any hydrated sphere.

Many of the reactions are sensitive to atmosphere and may spoil the reaction. In order to create an inert atmosphere nitrogen gas can be used using a glove box