Textbook 6D.15 Part B

[Evonne Xu 3I]

Hi, I was trying to set up the equation for the reaction, but I'm a bit confused on how to do it. The problem asks for the pH of AlCl3, but the solutions manual has it set up as Al(H2O)6+3 + H2O <-> H3O+ Al(H2O)5OH+2. I'm confused as to how to get there.

[Vyas_Koduvayur_2B]

Al3+ (aq) is usually just present as Al(H2O)63+ in solutions. So it is the same thing, just the conventional way of visualizing Al3+ in aqueous solutions. Everything else is the same, as you can note down the Ka of Al(H2O)6 and set up the equilibrium table.