I am predicting acid-base equilibria using the Brondsted-Lowry predictions. I am asked to do "solid aluminum sulfate added to water".

So I know there is an Al^2+ ion and a SO4^-2 ion, but does water dissociate into H30^+ and OH^-? If so, then H30^+ and OH^- would be the strongest acid and base...and I would end up with a neutral reaction (shouldn't it be acidic?). If not, then I would only have a strong base (SO4^-2), and no acid to work with. Help!

Also, if products are favoured, does that mean that the resulting solution is basic? And if reactants are favoured, the solution is acidic? Or is there no distinction?

Let's start over.

Al2(SO4)3 + H2O ==> Al^+3 (you had +2) + SO4^-2. Not balanced.
But it doesn't stop there.
Al^+3 actually is not that but Al(H2O)6 with +3 charge in solution. It is a hydrated ion with a +3 charge. It is acidic because it ionizes. It's tough to write on the board because I can't do subscripts and superscripts. Here is what happens. One of the H2O molecules that is in the hydrated ion splits into H^+ and OH^-. The H^+ reacts with H2O to form the H3O^+. What is left is the Al(H2O)5(OH)^+2. Now that you know what happens I'll do my best to write the equation.
Al(H2O)6(+3 charge) + H2O ==> Al(H2O)5(OH)^+2 + H3O^+.
The solution is acidic because of the H3O^+. The products are favored. But that means the solution is acidic. Where is this knowledge useful. Some plants don't grow well in basic soil; they need acidic soil. If a person has soil that is basic, s/he adds a little Al2(SO4)3 to the soil (solid S will do the same thing but it's a different reaction) and it becomes acidic (pH 5.5 -6--something like that) and those acidic plants thrive. (The S works because it's a bacteria found in the soil that eats on it and converts it to an acid.).

In order to determine whether water dissociates into H3O+ and OH- ions, we can consider its autoionization. Water has a slight tendency to dissociate into these ions, although the concentration of H3O+ and OH- is very small.

The autoionization of water can be represented by the equation:

H2O ⇌ H3O+ + OH-

In this equilibrium, water acts as both an acid (donating a proton, H+) and a base (accepting a proton, H+). H3O+ (hydronium ion) is formed when water acts as an acid, and OH- (hydroxide ion) is formed when water acts as a base.

The concentration of H3O+ and OH- ions in pure water at room temperature is approximately 1x10^-7 M each. Hence, water is considered to be neutral since the concentrations of H3O+ and OH- are equal.

However, when a substance dissolves in water, it can affect the concentrations of H3O+ and OH- ions, leading to an acidic or basic solution.

In the case of solid aluminum sulfate (Al2(SO4)3) added to water, the sulfate ion (SO4^-2) has no acidic properties to donate a proton (H+), and it acts only as a spectator ion in the solution.

On the other hand, the aluminum ion (Al^3+) has the potential to interact with water and act as an acid. It can form hydrated aluminum ions, such as Al(H2O)6^3+. The dissociation of these hydrated ions in water is relatively weak compared to strong acids.

Therefore, the addition of solid aluminum sulfate to water would result in a very minimal concentration of H3O+ ions, and the solution would remain close to neutral rather than being strongly acidic.

In summary, the addition of solid aluminum sulfate to water would not significantly increase the concentration of H3O+ and OH- ions, resulting in a relatively neutral solution.

To predict the acid-base equilibria in the reaction between solid aluminum sulfate and water, it is important to understand the dissociation behavior of both aluminum sulfate and water.

First, let's consider the dissociation of solid aluminum sulfate (Al2(SO4)3). When solid aluminum sulfate is added to water, it dissociates into its constituent ions:

Al2(SO4)3 (s) → 2Al3+ (aq) + 3SO4^2- (aq)

So, aluminum sulfate produces aluminum ions (Al3+) and sulfate ions (SO4^2-) in aqueous solution.

Now, let's discuss the dissociation of water. Water molecules can undergo autoionization, meaning they can self-dissociate into hydronium ions (H3O+) and hydroxide ions (OH-):

H2O (l) ↔ H3O+ (aq) + OH- (aq)

At room temperature, the concentration of hydronium ions (H3O+) and hydroxide ions (OH-) in pure water is very small, and the solution is considered neutral. However, this equilibrium is dynamic, and it can be impacted by the addition of other substances.

In the case of solid aluminum sulfate added to water, the aluminum ions (Al3+) and sulfate ions (SO4^2-) will remain as separate ions in solution. There is no direct involvement of water in the acid-base equilibrium because there is no direct interaction between water and these ions.

Thus, in this case, we don't need to consider the hydronium ions (H3O+) and hydroxide ions (OH-) as the acid and base, respectively. Instead, we look at aluminum ions (Al3+) and sulfate ions (SO4^2-) for acid-base reactions.

To determine whether the reaction is acidic or basic, we need to consider the relative strength of acid and base. In this case, sulfate ions (SO4^2-) can act as a base, whereas aluminum ions (Al3+) can act as an acid.

The sulfate ion (SO4^2-) is a relatively weak base, and the aluminum ion (Al3+) is a relatively weak acid. The reaction between these ions will result in a slightly acidic solution because the acid (Al3+) is stronger than the base (SO4^2-).

In summary, when solid aluminum sulfate is added to water, the solution becomes slightly acidic due to the acid-base reaction between aluminum ions (acid) and sulfate ions (base). The dissociation of water itself into hydronium ions (H3O+) and hydroxide ions (OH-) is not directly involved in this particular acid-base equilibrium.