18 LABORATORY EXERCISES. 



B. Neutralization. 



1. Pour a small amount of the hydrochloric 



acid into an evaporating-dish ; add caus- 

 tic soda, drop by drop, stirring continu- 

 ally with glass rod, until pieces of red 

 and blue litmus paper remain unchanged 

 when dropped into the liquid. (This 

 process is called neutralization.) 



2. Evaporate the liquid in the dish to dryness 



over an alcohol or gas flame. 



a. What is the appearance of the solid 



that is left? 



b. What is its taste? What substance, 



therefore, is made by combining 

 hydrochloric acid and caustic soda? 



C. Summary. From the above experiments 



1. Give some characteristics of an acid. 



2. Give some characteristics of an alkali. 

 3. How can you tell a neutral substance? 



4. Define neutralization. 



D. Applications. 



1. Drop small pieces of red and blue litmus 



paper into a solution of each of the fol- 

 lowing substances : soap of several kinds, 

 lemon juice, ammonia, cream of tartar, 

 saliva, baking soda, apple juice, sugar, 

 milk, white of egg, and other common 

 substances. 



2. Record your results by arranging all the 



substances you have tested in a table 

 like the following; 



