ACIDS, BASES, AND SALTS 171 



gen and one part of oxygen. If an acid is mixed with a base, 

 the hydrogen of the acid and the combination of hydrogen 

 and the oxygen of the base combine to form water. The 

 result is that both the acid and the base lose their character- 

 istics, and a salt is formed. This can be obtained by boiling 

 away the water. A salt, then, is the result of the combina- 

 tion of part of an acid with part of a base, water being formed 

 at the same time. We call this action neutralization. Most 

 salts do not affect litmus paper or phenolphthalein; that is, 

 they are neutral. 



Sometimes there is an excess of acid in a person's stomach, 

 which may be shown by testing the saliva with litmus paper. 

 Ordinary baking soda will neutralize the acid and " sweeten " 

 the stomach. See Section 208, Simple Household Remedies. 



Sour milk contains an acid which can be neutralized by 

 baking soda. Carbon dioxide, is set free from the baking soda 

 as fast as neutralization takes place. Cream of tartar has 

 acid characteristics, and for that reason is used with baking 

 soda to set free the carbon dioxide. The bubbles of this gas 

 cause the dough to rise. 



The soil tends to become slightly acid on account of the 

 excretions from the roots of plants. This acidity may be 

 corrected by the application of lime. See Section 158, The 

 Liming of the Soil. 



References : 



1. 1503 : 93. Acid Reaction of Root Hairs. 



2. 1702 : 72-77. Acids, Bases, Salts, and Neutralization. 



3. 1703 : 95-98. Acids, Bases, Salts Neutralization. 



o. 1701 : 106-109. Acids, Bases, and Salts Neutralization 



6. 1704 : 58. Acids, Bases, and Salts. 



c. 1705 : 28-29. Neutralization. 



d. 1706 : 87-98. Acids, Bases, and Salts. 



