Solution and Chemical Action 359 



stay blue. But if you put a piece of litmus paper into 

 something that is neither an acid nor a base, like sugar 

 or salt, it will still stay the same color. So, to test 

 for a base, use a piece of litmus paper that is pink and 

 see if it turns blue, or if you want to test for an acid, use 

 blue litmus paper. Do this experiment : 



Experiment no. With pink and blue litmus paper, test 

 the different substances named below to see which are acids 

 and which are bases. Make a list of all the acids and another 

 list for all the bases. Do not put down anything that is 

 neither acid or base. You cannot be sure a thing is an acid 

 unless it turns blue litmus pink. A piece of pink litmus 

 would stay pink in an acid, but it would also stay pink in 

 things that were neither acid nor base, like salt or water. 

 In the same way you cannot be sure a thing is a base unless 

 it turns pink litmus blue. Here is a list of things to try: 

 i, sugar; 2, orange; 3 , dilute sulf uric acid ; 4, baking soda 

 in water; 5, alum in water; 6, washing soda in water; 

 7, ammonia; 8, dilute lye; 9, lemon juice; 10, vinegar; 

 n, washing powder in water; 12, sour milk; 13, corn- 

 starch in water; 14, wet kitchen soap; 15, oil; 16, salt in 

 water. 



You may have to make the orange and sour milk test 

 at home. You may take two pieces of litmus paper 

 home with you and test anything else that you may 

 care to. If you have a garden, try the soil in it. If it 

 is acid it needs lime. 



Application 81. A boy spilled some greasy soup on his 

 best dark blue coat. Which of the following methods would 

 have served to clean the coat? to sponge it (a) with cold 

 water ; (b) with water (hot) and ammonia ; (c) with hot 

 water and vinegar; (d) with concentrated nitric acid; to 

 sprinkle lye on the spot and pour boiling water over it. 



