AAMC9: How do you recognize a buffer solution?

[sudo]

So, I thought buffer solutions are either:

• Weak acid + conj. base, OR
• Weak base + conj. acid

According to this (question from AAMC9), HClO and NaClO are a buffer solution. I thought HClO would be considered a strong acid (because of HCl), not weak acid!

Can someone make any sense of this for me? 😕


Also...after looking at this question, under what circumstances (if any) would adding a strong acid or base to a buffer solution cause a "significant" pH change?

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[MedPR]

HClO is a weak acid and has nothing to do with HCl. The central atom is the oxygen.

For MCAT purposes, adding a strong acid/base to any buffer will not cause significant change. In reality, you would have to add a large volume.

 

[gettheleadout]

Editing title for AAMC9 spoiler. Come on guys...

 

[illinichief89]

HClO is hypochloric acid which is a weak acid. NaClO is going to dissociate in an aqueous solution. ClO- is the conjugate base to HClO. When you want to make a buffer solution that is resistant to pH changes, you want equal amounts of Acid and its conjugate base or Base and its conjugate acid. Since this is a buffer solution you need to add alot of base to this solution to raise its pH.

HCl which is Hydrochloric acid is a strong acid. This is different than HClO because of the oxygen atom.
HClO4 which is perchloric acid is also a strong acid.

 

[sudo]

Thank you guys! 🙂 Makes more sense now