ACIDS BASES SALTS ANHYDRIDES, ETC. 25 



(a) They are sour to the taste. 



(6) They have the power of turning to a pink color 

 paper that has been stained blue by an organic dye com- 

 monly called litmus. 



(c) When in water solution, they attack such metals 

 as zinc and magnesium, thereby being themselves broken 

 up into hydrogen or some compound of hydrogen, as one 

 of the decomposition products. Most frequently, this action 

 may be observed by the bubbles of effervescing gas rising 

 through the liquid acid solution. 



(d) They arc soluble in water. They differ, however, 

 in degree of solubility. 



(e) They contain hydrogen, which is easily separated 

 from the remainder of the acid when it acts chemically 

 upon other substances. 



(/) Acids react with bases, thereby neutralizing or de- 

 stroying the characteristic properties of both acid and 

 base. 



(g) In respect to their composition, acids may be divided 

 into two classes: 



(1) The Oxygen Acids. These are composed of hydrogen 

 which is bound by means of oxygen to a non-metallic ele- 

 insnt or radical. For example, hypochlorous acid, HC1O, 

 may be considered as H O Cl; nitric acid as H O NO^; 



H (X 



sulphuric acid as >SO2. 



H CK 



(2) Hydrogen Acids. These do not contain oxygen. 

 The formula of the six common hydrogen acids are HC1, 

 HBr, HF, HI, H 2 S, HCN. 



24. Bases. Some of the most common bases are sodium 

 hydroxide, NaOH; potassium hydroxide, KOH; ammo- 

 nium hydroxide, NH-iOH; calcium hydroxide, Ca(OH)2j 

 barium hydroxide, Ba(OH)o. Bases have, generally, prop- 

 erties the opposite of those exhibited by acids. 



(a) Bases that are soluble in water have an alkaline 

 taste and feel soapy to the touch. 



