Fig. 2.8

Tap. 26a

Tap. 26b

Fig. 2.9

Fig. 2.10

In Neutral solutions there will

be a number of OH– ions equal to

the number of

H+ ions

Fig. 2.11

In Acidic solutions there will always be more H+ ions than there are

OH- Ions

Fig. 2.12

In Basic (alkali) solutions there is always a greater number of OH- ions than there

are H+ Ions

Tap. 28

Even in pure distilled water, the water molecules will dissociate, but the number of H+ ions will

always equal the number of OH- Ions

In one liter of distilled water there will be 10-7 X Avagadros number (6.02 X 1023 ) of H+ ions

10-7 = 0.000 0001 X Avagadros number of H+ ions per liter. This is a pH of “7” . So something with a pH of 2 would be 10-2 = 0.01 X Avagadros number of H+ ions

per liter. That means the pH number of 2 has way more H+ ions, way more acidic

Fig. 2.13

Tap. 29

Buffers are chemicals that take up either excess H+ ions or excess OH- ions to help

maintain a given pH at the level it is supposed to stay at.

In the above reaction, Bicarbonate ions act as a buffer to take up the excess H+ ions. During this reaction Carbonic Acid is produced, when

Carbonic Acid is carried to the lungs it will dissociate into H2O and CO2 and be exhaled from the body. See Below

H2CO3 H20 + CO2

Fig. 2a