Neutralizatioins for weak acids & weak bases

[Addallat]

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Does a neutral pH eventually result when weak acids and bases react?


TPR is confusing the heck out of me, on page 195 they state that "reactions that involve a weak acid or base will generally not be a pH neutral"

then on the bottom of the page it states "regardless of the strengths of acids and bases, all neutralization reactions go to completion"


so am i to assume that the pH won't be neutral at first for a weak acid and weak base, but over time it'll become neutral?


meant to post in Q&A forum sorry

 

[tuhtles]

For titration of strong acids/bases, the ph at the end point will always be 7 or "neutral".

However, for titration that includes weak acids/bases, the ph of the end point will NOT be 7. Instead, it will be either above 7 or lower than 7 depending on the situation.

Let's say you are titrating a weak base with a strong acid. As the strong acid neutralizes the weak base, the product from this neutralization will be the conjugate acid of the weak base. As the titration continues, the strong acid will continue to react with the strong base to produce more of the conjugate acid of the weak base. Therefore, at the end point when the reaction is complete, you will end up having "extra" acid that was created from the neutralization reaction. So in this case, the pH at the end point will be less than 7 (acidic) due to the conjugate acid that was produced in the neutralization process.

 

[gettheleadout]

Yeah, it can be a bit confusing at first that "neutralization" of an acid or base doesn't necessarily mean achieving a neutral pH.

Neutralization means combination of equal moles acid and base, regardless of their strength or concentration.

 

[Xeones]

Does a neutral pH eventually result when weak acids and bases react?


TPR is confusing the heck out of me, on page 195 they state that "reactions that involve a weak acid or base will generally not be a pH neutral"

then on the bottom of the page it states "regardless of the strengths of acids and bases, all neutralization reactions go to completion"


so am i to assume that the pH won't be neutral at first for a weak acid and weak base, but over time it'll become neutral?


meant to post in Q&A forum sorry

"Strong" means that the acid/base essentially fully dissociates in water.

Strong acid strong base - pH 7
Strong acid weak base - pH <7
Weak acid strong base - pH >7
Weak acid weak base - no titration happens with this combination