6D11 E and F

[Jedrick Zablan 3L]

Hello! Can anyone help me with E and F on 6D11? How do I write the chemical equation for those? Thanks!

Decide whether an aqueous solution of each of the follow- ing 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. (a) NH4Br; (b) Na2CO3; (c) KF; (d) KBr; (e) AlCl3; (f) Cu(NO3)2.

[Ryan 1K]

When the salts are in an aqueous solution, the cation and anion will react differently. In the case of AlCl3, the small, highly positive Al3+ cation will interact with the water molecules and will cause the water molecules to give up a proton, acting as an acid. The Cl- anion is the conjugate base of a strong acid, HCl, so we know that it will be a weak base. As such, the solution will have a pH < 7.

As for writing the chemical equations, the Cl- ions, since they don't react, will cancel out, leaving just the Al3+, which will react to water to form H3O+ ions.