The Foundations of Chemistry

These definitions do notspecify that an electron pair must be transferred from one atom

to another—only that an electron pair, residing originally on one atom, must be shared

between two atoms. Neutralizationis defined as coordinate covalent bond formation.

This results in a covalent bond in which both electrons were furnished by one atom or

ion.

The reaction of boron trichloride with ammonia is a typical Lewis acid–base reaction.

388 CHAPTER 10: Reactions in Aqueous Solutions I: Acids, Bases, and Salts

The Lewis theory is sufficiently general that it covers allacid–base reactions that the other

theories include, plus many additional reactions such as complex formation (Chapter 25).

The autoionization of water (Section 10-5) was described in terms of Brønsted–Lowry

theory. In Lewis theory terminology, this is also an acid–base reaction. The acceptance

of a proton, H
, by a base involves the formation of a coordinate covalent bond.

B

Cl Cl

Cl

+ N

H

H

H

Coordinate

covalent bond

Cl

B N

H

H

Cl

Cl

H

Bon

dformed

BCl 3 (g)

acid

+NH 3 (g)

base

Cl 3 B : NH 3

product

B

:

:

:Cl

:Cl::

:

:Cl: N

H

H

H

Bondformed

+ B

:

:

:Cl

:Cl::

:

:Cl: N

H

H

: H