HW 6D.11 part e

[CNourian2H]

6D.11 Decide whether an aqueous solution of each of the following salts has a pH equal to, greater than, or less than 7. If pH . 7 or pH , 7, write a chemical equation to justify your answer. (e) AlCl3;

I am confused how to write the equation for Al +3. Why does it combine with H20 first?

[Chem_Mod]

Look over your notes concerning small metal cations acting as acids. These include many transition metal cations like Al3+. They will first form coordinate covalent compounds with water. These water molecules then lose their proton to free-floating water molecules, forming hydronium. The water on the coordinate covalent compound that lost its proton will become hydroxide, thus lowering the charge on the Al to Al2+. This can happen for each coordinated water molecule until Al reaches neutral charge