From what I've read, [Cu(H2O)6]2+ when reacts with concentrated hydrochloric acid, the chloro ligand will displace the aqua ligand and form [CuCl4]2-
[Cu(H2O)6]2+ + 4Cl- <--> [CuCl4]2- + 6H2O
( <---> means reversible reaction, I don't know how to type it out, sorry)
The Attempt at a Solution
But chloro is a weaker ligand than aqua, how can the ligand substitution reaction happen?