ACIDS BASES SALTS ANHYDRIDES, ETC. 27 



non-metallic or acid radical, SO4, the result will be the 

 salt, zinc sulphate, ZnSO4| replacing the hydroxyl of 

 sodium hydroxide by the non-metallic element, chlorine, 

 the result will be a salt, sodium chloride, NaCl. 



(c) When acids and bases react with each other, water 

 is always produced by the union of the hydrogen of the 

 acid with the hydroxyl of the base, H+OH = H20. What 

 is left of the acid after its hydrogen is removed is the acid 

 radical. For example: NOs from nitric acid, HNOs. 

 What is left of the base after its hydroxyl is removed is 

 the metal: For example, K from the base potassium hy- 

 droxide, KOH. These remnants will unite and thereby 

 form a salt; K and NOa produce the salt potassium nitrate, 

 KNOa. 



There are four classes of salts: 



(1) Normal Salts. These contain only the metal and 

 the acid radical, such as sodium nitrate, NaNOa, or potas- 

 sium phosphate, KaPCU. They may be regarded as the 

 salts in which all the hydrogen of the acid has been replaced 

 by a metal. 



(2) Acid Salts. In these one or more of the hydrogens 

 of the acid from which the salt is derived has been re- 

 tained. For example: sodium hydrogen sulphate, NaHSO4, 

 potassium hydrogen phosphate, KHSO4. These generally 

 are able to turn blue litmus to a pink^color on account of 

 the acid hydrogen left in them. 



(3) Basic Salts. In these, some of the hydroxyl of 

 the base from which the salt was derived has been retained. 

 For example, basic bismuth nitrate, Bi(OH)2NOs. This is 

 produced by substituting the acid radical NOs for one 

 of the hydroxides of the base, Bi(OH)a. 



(4) Neutral Salts. These salts, when in water solu- 

 tion, do not change color hi either blue or pink litmus 

 paper. 



26. Anhydrides. This word means without water. An- 

 hydrides may be considered as either acids or bases from 



