364 Common Science 



things: soap, oil, lemon, flour, peroxide, ammonia, iodine, 

 baking soda, essence of peppermint. Which should she have 

 put on the boy's hand ? 



Application 84. A teacher spilled some nitric acid on her 

 apron. On the shelf there were : hydrochloric acid, vinegar, 

 lye, caustic soda, baking soda, ammonia, salt, alcohol, kero- 

 sene, salad oil. Which should she have put on her apron? 



Application 85. A boy had " sour stomach." His sister 

 said, " Chew some gum." His aunt said, " Drink hot water 

 with a little peppermint in it." His mother told him to take 

 a little baking soda in water. His brother said, " Try some 

 hot lemonade." Which advice should he have followed? 



Application 86. Two women were bleaching a faded pair 

 of curtains. The Javelle water which they had used was 

 made of bleaching powder and washing soda. Before hang- 

 ing the curtains out to dry, one of them said that she was 

 afraid the Javelle water would become so strong as the water 

 evaporated from the curtains that it would eat the curtains. 

 They decided they had better rinse them out with something 

 that would counteract the soda and lime in the Javelle 

 water, and in the laundry and pantry they found: am- 

 monia, blueing, starch, washing powder, soap, vinegar, and 

 gasoline. Which of them, if any, would it have been well 

 to put in the rinsing water? 



Inference Exercise 



Explain the following : 



531. Solid pieces of washing soda disappear in hot water. 



532. Greasy clothes put into hot water with washing soda become 



clean. 



533. If you hang these clothes up to dry without rinsing them, the 



soda will weaken the cloth. 



534. Lemon juice in the rinsing water will prevent washing soda 



from injuring the clothes. 



535. If you hang them in the sun, the color will fade. 



536. A piece of soot blown against them will stick. 



537. A drop of oil that may spatter against them will spread. 



