Sapling #6

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haley f
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Sapling #6

Postby haley f » Sun Jan 17, 2021 6:02 pm

Classify these salts as acidic, basic, or neutral.
NaCN, KCl, NH4CLlO4, K2CO3, LiClO4

I know that you have to determine if these salts came from a weak or strong acid or base but I keep getting confused of what means what. If a salt is the conjugate acid of a weak base, is the solution acidic?

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Re: Sapling #6

Postby reva_bajjuri » Sun Jan 17, 2021 6:44 pm

hi! the difference between strong acids and weak acids (and strong bases and weak bases) is that the first dissociates completely in solution to form Hydronium(or hydroxide ions) and the second only dissociates partially. The conjugate bases of strong acids are very weak bases with almost no affect on the solution. The conjugate acids of strong bases also have minimal effect on the solution. The conjugate bases of weak acids are weak bases. These bases do make the solution somewhat acidic. The conjugate acids of weak bases are similarly weak acids. These weak acids make the solution somewhat acidic. There should be a chart detailing all of this in the textbook. Hope this helps!

Stuti Pradhan 2J
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Re: Sapling #6

Postby Stuti Pradhan 2J » Sun Jan 17, 2021 6:46 pm

If the salt has the conjugate acid of a weak base, the solution will be acidic because the conjugate acid will attract the OH- from water and leave H+ ions behind, making the solution acidic. It is also important to note that the other ion (in this case the anion) must be a spectator ion in this situation.

The opposite is also true, so the conjugate base of a weak acid will make the solution basic because the anion will attract the H+ ion, leaving behind OH- ions, which will make the solution basic.

Hope this helps!

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Re: Sapling #6

Postby Dylan_K_3B » Sun Jan 17, 2021 6:47 pm

You look at the cation and anion individually in the salt to determine if the salt itself is neutral, acidic, or basic. For example with NaCl, Na+ would be derived from NaOH which is a strong base, and Cl- is derived from HCl which is a strong acid. Therefore the reaction between these two creates the neutral salt NaCl (strong acid and strong base). Now using NH4Cl as an example, NH4+ is derived from NH3 which is a relatively weak base, and Cl- once again comes from a strong acid, making it a very weak base. So this salt would be acidic, with NH4+ acting as the acid.

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