Question 12.65

Annah Khan 1B
Posts: 28
Joined: Fri Jul 22, 2016 3:00 am

Question 12.65

"Determine whether an aqueous solution of each of the following 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."

I understand what the question is asking me to do, but I am unsure how to do it. Could someone please explain this to me? Thanks in advance!

Chem_Mod
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Joined: Thu Aug 04, 2011 1:53 pm
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Re: Question 12.65

You would have to write out the net ionic equation and look @ the compounds that would be formed. If the salt would form a weak acid/base in the products, you'll know the pH of the solution. For example:

$KF + H_2O \rightleftharpoons HF + OH^- + K^+$

Since HF is a weak acid, it won't dissociate back into H+ and F-, which means the final product is basic (due to the OH-) from the addition of the salt. For salts that form strong acids/bases, the backwards dissociation will occur, which would mean the salt creates a neutral solution.

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