AlCl3

[505400967]

I came across this compound in textbook question 6D.11. Can someone explain how aluminum will act as an acid?

where does the Al(H2O6) molecule come from ?

[Michelle Yeung 3I]

Hi! I'm not sure if this was taught in this course yet. 6D.11 is not included in the assigned textbook questions so I am assuming this is beyond our current scope of the course.

[Caitlyn Nguyen 2A]

If my understanding is correct, aluminum will act as an acid because, when aluminum is dissolved in water, the Al3+ will bond with the OH- from the water to produce (Al(OH))2+ and H+.

I believe the Al(H2O6) molecule comes from when these H+ protons that were produced bond with the surrounding water molecules from the aqueous solution and form H3O+.

[Levy Shaked]

Agreed. Highly charged, small metal ions like aluminum act as acids in solution because, as they are hydrated by water molecules, they polarize them due to their positive charge; the result is each water's molecular electrons being drawn towards the cation and away from one of the water's hydrogen atoms, forming a dipole with a partial charge on this H+ ion. This increases the stability of H-bonds that this partially charged hydrogen atom forms with other water molecules, making it more likely that proton transfer will occur to form H3O+.