Barrons SAT Subject Test Chemistry, 13th Edition

The acid–base systems are summarized below.

Type

Acid

Base

Arrhenius

H + or H 3 O+ producer

OH – producer

Brønsted-Lowry

proton (H +) donor

proton (H +) acceptor

Lewis

electron-pair acceptor

electron-pair donor

Acid Concentration Expressed as pH

Frequently, acid and base concentrations are expressed by means of the pH

system. The pH can be defined as −log [H+], where [H+] is the concentration of
hydrogen ions expressed in moles per liter. The logarithm is the exponent of 10
when the number is written in the base 10. For example:

REMEMBER

pH = −log[H+]

The logarithms of more complex numbers can be found in a logarithm table.
An example of a pH problem is:
Find the pH of a 0.1 molar solution of HCl.

1st

step.

Because HCl ionizes almost completely into H+ and Cl

−, [H+] = 0.1 mole/liter.

2nd

step.

By definition

pH = −log [H+]

so