6D 11 E

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Jamie Lee 1H
Posts: 54
Joined: Fri Aug 09, 2019 12:15 am

6D 11 E

Postby Jamie Lee 1H » Wed Dec 04, 2019 9:18 pm

Decide whether an aqueous solution of each has a pH equal to, greater than, or less than 7.
How do you determine this for E) AlCl3?

connie 2C
Posts: 106
Joined: Thu Jul 11, 2019 12:17 am

Re: 6D 11 E

Postby connie 2C » Thu Dec 05, 2019 11:05 am

i found someone else who answered the same question and this was their response: (credit to sierra cheslick 2B) "This is a salt, and it dissociates in water. Since Cl- is the conjugate base of a strong base, it is very weak and therefore considered to not affect pH and can be left out of the equation. Al3+, however, can pull water molecules towards it and form coordinate covalent bonds, since it is a small and highly charged cation. These coordinate covalent bonds weaken the the O-H bonds by pulling electrons towards the Al, and allow hydrogens to detach from the water molecules. This forms H3O+, meaning Al3+ acts as a weak acid. To solve for the pH, set up and ICE box with the concentration of Al3+ minus x, and the initial concentration of H3O+ (0 M) plus x. Then solve for x using the Ka value for Al3+ (1.4 x 10^-5)"

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