Resonance.-If the group X may act as a donor of electrons in an acid of the type XB (OH) z, then the structure X+= B-(OH) z will be in resonance with the forms XB (OH) z, XB-< o+ H, and XB-/. Since the negative part of the dipole in the structure X*= B-(OH) 2 is nearer the dissociating hydrogen atom than is the positive pole, the effect of this structure is to decrease the strength of the acid. The extent of the contribution of X+= B-(OH) z to the structure of ...