CHAPTER XVI 



ACIDS, BASES, AND NEUTRAL SUBSTANCES 



Introduction. In every kitchen may be found three 

 things: vinegar, ammonia, and common salt. They 

 are three examples of three great classes of com- 

 pounds. Vinegar belongs with the acids. Ammonia 

 belongs with the bases. Common salt belongs with the 

 general group of salts. 



Acids. There are many acids with which you are 

 already familiar. There is not a boy, at least, who 

 does not know of the sour, puckery juice of a green 

 apple. The grape, the peach, the plum, and practi- 

 cally all other fruits are characterized in their early 

 stages by their distinctly acid taste. The lime, the 

 lemon, and some other fruits retain this acid even 

 in the ripened form. Sweet cider when exposed to 

 the air becomes sour and acid. Most of the acids 

 which we know in the home come from the plant 

 world. There are other acids, however, w r hich are 

 prepared and used in almost countless processes in 

 shops and factories. The three most important of 

 these are hydrochloric acid, sulphuric acid, and nitric 

 acid. 



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