Conjugate Acid/Base strength. (1 Viewer)

[Ioup]

I understand that a Strong (acid,base) forms an extremely weak (acid, base) but I'm a little bit confused on what weak (acids,bases) form.
One textbook is saying a weak(acid, base) forms a moderately weak (acid or base). Whilst another is saying, for example, a weak base forms a strong acid.
Not sure which one to trust, although the textbook which says a weak base forms a strong acid is a bit untrustworthy......

 

[Dreamerish*~]

Welcome to BoS, Ioup.

The conjugate base of a strong acid is an extremely weak base. This means the acid ionises completely in water (let's just call 99.9% ionisation "complete"). Consequently the conjugate bases do not react significantly to form the acid molecule again.

The conjucate base of a weak acid is a weak base. So both acid and base react with water to a certain extent. If the conjugate base reacted as little as that of a strong acid, then the weak acid wouldn't be weak. It is the reverse reaction - that is, the reaction between the conjugate base and water - that reduces the acidity of the weak acid.

The conjugate base of an extremely weak acid is a strong base. The base reacts with water to a greater extent than the acid, because if it didn't, the acidity of the solution would be high.

Similarly, the conjugate acid of a strong base is an extremely weak acid, and the conjugate acid of a weak base is a weak acid.

I hope I'm making sense.

 

[Ioup]

Thanks for that.