Question

Is my understanding of acidity/ basicity correct? Arranging them in order is confusing.

In arranging acidity:

- if the molecules have no charge, consider their conjugate bases: the most stable conjugate base (most stabled negative charge; element effect: high electronegative atom, bigger atom/ inductive effect: the presence of e-withdrawing/ resonance/ hybridization effect: increased %s character)

- if the molecules have + charges, conjugate bases are not considered. The most unstable + charged molecule would be the strongest acid. (most unstable positive charge; element effect: low electronegative atom, bigger atom/ inductive: presence of e-donating/ resonance/ hybridization: lower %s-character)

In increasing basicity:

- More basic will be the more unstable negatively charged molecule

- More basic will be the more stable conjugate acid

Is my understanding correct? Please help me clarify these relationships.

Thank you.

Answer 1

Your understanding is correct.

There is an equilibrium between conjugate acid and base pair.The equilibrium lies towards weak partner.Here weak means stable.

Strong base has weak conjugate acid and vice versa.

Stability of negatively charged conjugate base depends on stability of charge,high electronegativity.with s character electronegativity increase.e-withdrawing group with resonance stabilise charge.

About positive charged acid.most unstable positive charge ismost reactive and least stable and loses the charge.low electronegative atom ,less s character and electron donating ability makes it easy to lose the charge.

More basic is more prone to donate the electron pair and it increases with electron donating group.Less s character is preferable. Most bases are neutral having donatable lone pair.defining bases on charged would be compartmentalizing.

So more donation more basic.

Strong base stable conjugate acid.