Decide 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)
How do we determine this?
Textbook 6d.11
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Kenneth Lin 2G
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Re: Textbook 6d.11
The Br- does not contribute to pH, so you are left with the conjugate base.
This will be: NH4+ + H2O<---> NH3 +H3O+, which shows the pH is less than 7.
The Na2CO3 also follows the same guidelines.
This will be: CO32-+ H2O <----> HCO3- +OH-. This will be a basic solution, meaning the pH is greater than 7.
Follow the format for the rest of the questions and remember that cations or anions from strong bases or acids do not affect the pH. Just use the conjugate base or acid and write out the chemical equations to determine the pH.
This will be: NH4+ + H2O<---> NH3 +H3O+, which shows the pH is less than 7.
The Na2CO3 also follows the same guidelines.
This will be: CO32-+ H2O <----> HCO3- +OH-. This will be a basic solution, meaning the pH is greater than 7.
Follow the format for the rest of the questions and remember that cations or anions from strong bases or acids do not affect the pH. Just use the conjugate base or acid and write out the chemical equations to determine the pH.
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