DAT Destroyer GenChem 2010 #171

[CometBru]

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30.0 ml of 0.20M Ba(OH)_2 is requires to neutralize 25 mL of citric acid, H3C6H5O7. What is the Molarity of the H3C6H5O7?

My interpretation of this question could not bring me to the answer to this question out for two reasons, first, is acetic acid strong, thus will it completely deprotinate? Additionally, after finding out that it's not strong, there is not way that it will go through all three deprotinations so it won't "neutralize" as it says it would. There weren't any pKa's or pKb's in there either... so after finding out that the question is treated as though there WILL be three successive deprotinations all in a "strong" fashion, it kind of got me confused.

I must be missing something, would someone mind helping me find the missing piece?

 

[Likkriue]

Acetic acid isn't strong, but what you have there is citric acid which isn't acetic acid.

Citric acid has 3 protons that can be donated. Look up a pka table for the protons on citric acid and you will see they can all disassociate.

 

[CometBru]

Acetic acid isn't strong, but what you have there is citric acid which isn't acetic acid.

Citric acid has 3 protons that can be donated. Look up a pka table for the protons on citric acid and you will see they can all disassociate.

Yes citric acid, sorry. I understand that all three CAN dissociate, but they wouldn't all three dissociate, giving all three deprotinations strong acid characteristics.

 

[rdub]

Ba(OH)2 is a strong base. Even if citric acid isn't a strong acid, it can still have its protons ripped away by the high concentration of base.