Question About Deprotonation

[RiPSTONE]

---

Members don't see this ad.

Why is a strong base used to deprotonate a very weak acid? I was under the assumption that the reason for using a strong base was to deprotonate a strong acid.

 

[sillyjoe]

Strong acids don't need a strong base to deprotonate because they have high Ka's.

Weak acids have low Ka's and in order to deprotonate it you use a strong base.

 

[Czarcasm]

Why is a strong base used to deprotonate a very weak acid? I was under the assumption that the reason for using a strong base was to deprotonate a strong acid.

Because the conjugate base of a very weak acid is a very strong base. With acid-base reactions, you will always have one strong side and one weak side, ie. Stronger Base + Stronger Acid ---> Conjugate Acid + Conjugate Base. In this instance, you want the base you use to be considerably stronger than the base produced by the weak acid. Also, the very weak acid is still stronger than the conjugate acid of the very strong base (of course because gaining a proton makes the strong base very stable; this is essentially why it's so strong in the first place). Sorry my explanation is kinda convoluted and I'm tired so I doubt it makes much sense.