6D.15b

[Minahil_Tufail_3I]

For this problem, how do you find the Ka value for AlCl3?
Calculate the pH of (b) 0 .055 M AlCl3.

[Shanna Yu 1C]

Hi!

So for this, I think it's good to know that Cl won't be included in this whole thing, as it doesn't affect the pH. Al3+ is the (weak) acid, here, as it attracts water molecules enough that said water's hydrogen atoms break off. The reaction goes like this, I think: Al(H2O)6 3+ + H2O ---> H30 1+ + Al(H2O)5OH 2+ It looks weird, but it's just due to excess of water.

From here, we can grab the Ka value for Al3+ from the table that the textbook has at around 478, which is 1.4 x 10^-5. Now we have the Ka, and all you need to do from here is get your equilibrium constant ratio-type thing from the reaction above and proceed as usual with our ubiquitous ICE table.

Lemme know if you need clarification!

[Sarah_Hoffman_2H]

Just to clarify, you would need to look at the table to find the Ka value, in this problem you are not expected to solve for it.

[Sophia Stewart 3F]

Just to clarify, you would need to look at the table to find the Ka value, in this problem you are not expected to solve for it.

You need to look at the table.