(b) Dilute still more, and then determine the taste as in 

 the preceding experiment. 



(c) By means of a rod, put a drop of the solution on a 

 small piece of blue litmus paper. What is the result? 



(d) Put a drop on red litmus paper. What is the re- 

 sult ? 



(e) Repeat (a), (b), (c), and (d) for limevvater and 

 liquid ammonia. 



Dissolve some baking soda in warm water and test. Is 

 it an acid or a base ? 



What are the characteristics of bases, and how could you 

 detect the presence of a base in an unknown substance ? 



A solution which turns blue litmus red is said to have 

 an acid reaction ; a solution which turns red litmus blue is 

 said to have an alkaline (basic) reaction. 



EXPERIMENT 61. NEUTRALIZATION 



To a solution of caustic soda, add very slowly and gradu- 

 ally small quantities of hydrochloric acid, testing the re- 

 sulting solution from time to time with fresh pieces of red 

 litmus paper. Add acid until the red litmus paper is not 

 affected by the acid-base solution. 



When this point is reached, test the solution as to taste 

 and feeling. Is there any well known substance which it 

 tastes like ? 



If an acid and base are mixed in the proper proportions, 

 the result is a solution which has neither an acid nor a bit- 

 ter taste, nor a slimy feeling. The new substance has 

 none of the properties of either of its components, and the 

 acid and base are said to have neutralized each other. 



