Acidic, basic, or neutral?

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Marisa Gaitan 2D
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Acidic, basic, or neutral?

Postby Marisa Gaitan 2D » Wed Dec 09, 2020 11:54 am

What is the general method of identifying whether a salt is acidic, basic, or neutral? I'm a little confused on this concept, thanks!

Chem_Mod
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Re: Acidic, basic, or neutral?

Postby Chem_Mod » Wed Dec 09, 2020 12:27 pm

The general method for identifying an acid/basic/neutral salt would be to identify what effect on pH each cation/anion in the salt has. For example, if the salt is NaF, the cation here would be Na+ and the anion here would be F-. We know that NaOH --> Na+ + OH-. Since NaOH is a strong base, the Na+ will be weak and will have no effect on pH. We know that HF --> H+ + F-. Here, since HF is a weak acid, then the F- will be a weak base. Put together, if the Na+ is neutral and the F- is basic, NaF will be a basic salt.

Joseph_Armani_3K
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Re: Acidic, basic, or neutral?

Postby Joseph_Armani_3K » Wed Dec 09, 2020 3:27 pm

It's all in whether or not the ions can form a strong acid/base or a weak acid/base. If both the acid and base are strong, the ion is neutral. If one's a weak acid and the other a strong base, the salt is basic. If one's a strong acid and the other a weak base, the salt is acidic.

DMaya_2G
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Re: Acidic, basic, or neutral?

Postby DMaya_2G » Wed Dec 09, 2020 8:46 pm

We determine whether the salt is acidic or basic by comparing the Ka and Kb values for the ion. Hence, if Ka > Kb, the ion is acidic. In contrast, if Kb > Ka, the ion is basic.

Vanessa Perez
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Re: Acidic, basic, or neutral?

Postby Vanessa Perez » Wed Dec 09, 2020 9:34 pm

Thank you!!! this was very helpful, I was confused on this topic.

Ayesha Aslam-Mir 3C
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Re: Acidic, basic, or neutral?

Postby Ayesha Aslam-Mir 3C » Thu Dec 10, 2020 10:51 pm

In the lecture from Wed, Dr. Lavelle uses HCl + NH3 --> NH4Cl and explains that the ammonium cation makes the solution acidic. Why is that? Is it based on conjugates or does NH4 donate a proton in solution?

Xavier Herrera 3H
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Re: Acidic, basic, or neutral?

Postby Xavier Herrera 3H » Sat Dec 12, 2020 1:12 pm

The solution is acidic because NH4Cl has a strong acid and weak base. The Cl- is from a strong base, so it won't change the pH. However, the NH4+ isn't from a strong acid or base, so it will react with water. It will donate its H+ to water to form H3O+, making the solution acidic, because NH4+ + H2O ----> NH3 + H3O+

Heidi Buri 2I
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Re: Acidic, basic, or neutral?

Postby Heidi Buri 2I » Sat Dec 12, 2020 8:15 pm

Hi! To observe if a salt is acidic, basic, or neutral, it helps to observe what happens after the salt is dissolved in a solution. After the salt is dissolved in a solution, if an acidic solution is produced, the salt has acidic character. After the salt is dissolved in a solution, if a basic solution is produced, the salt has basic character.

rhettfarmer-3H
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Re: Acidic, basic, or neutral?

Postby rhettfarmer-3H » Tue Dec 15, 2020 11:24 pm

I think the main way to focus on the equation that makes the salt. So, for example, NaCl is made of NaOH and HCl strong base and acid so they cancel to be neutral. As for the others if we have a strong acid and weak basic is a acid salt and another is a if a strong base and weak acid therefore, its a basic salt.


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