Bondline / Reactions

Acid–base proton transfer

The base uses a lone pair to take the proton; the O–H electrons stay on oxygen. The equilibrium favours the side with the weaker acid (higher pKa).

Acids and bases · 1 step

Conditions

Ethanoic acid (pKa 4.8) and hydroxide (water pKa 15.7): lies far to the right.

Mechanism

Red curly arrows show where each pair of electrons moves.

OHOHO−OO−H2O++
MechanismHydroxide takes the acidic proton; the O–H bonding pair becomes a lone pair on the carboxylate oxygen.

About acids and bases reactions

An acid–base reaction moves a proton from an acid to a base. Curly arrows start from the base's lone pair, and the old bond's electrons stay on the conjugate base.

Practise this mechanismDraw the curly arrows yourself and Bondline checks each one. Or add it to your notes and watch it in 3D.

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