Question

How to prepare stock solution of aluminium trichloride?

Answer 1

Just add water, stirr, a bit of heat would help but not too much. Seriously water plus AlCl3 is a very powerful almost explosive reaction, lots of heat comes out of it. So you will have to add the water carefully. A simple method is take your AlCl3 and leave it out in the open for a few days, it will absorb ambient humidity and then adding more water will be by far less explosive. Or add water with a steam bath. Easy to build, take a pot with a lid add hot water in it, and place your AlCl3 in a cup so that it does not get wet or floats, close the lid and wait for a bit.

Reference https://www.physicsforums.com/threads/can-i-prepare-aluminum-chloride-hexahydrate-solution-frm-aluminum-chloride-powder.374281/