ACIDS, BASES AND SALTS 147 



Borax Molasses 



Cream of tartar Lime-water 



Your saliva Baking soda 



2. Place about 10 cubic centimeters of sodium hydroxide (NaOH) in 

 an evaporating dish. Is it an acid or a base? 



3. Add hydrochloric acid, drop by drop, to the sodium hydroxide, 

 testing after each addition of acid until the solution is neutral. Be 

 careful not to add too much acid. Evaporate the liquid, taste and name 

 the substance left in the dish. 



4. Write the chemical formulas for the acid and base used in the 

 preceding experiment and cross out the chemical elements found in the 

 salt. Can you tell from the remainder, what the liquid was that you 

 evaporated ? 



6. Baking soda is often added to sour milk to "sweeten" it, that is, 

 to remove the sour taste. Explain how this is accomplished. 



6. The pain from insect stings is usually due to formic acid introduced 

 into the wound. Why does the application of ammonia reduce the pain? 



7. Strong acids rapidly destroy the skin, clothing, and other sub- 

 stances. If one spilled acid on hands or clothing, what could be used to 

 render the acid harmless? 



8. Burns produce an acid condition of the flesh. Why apply lime- 

 water? 



9. Soils sometimes become sour through the accumulation in them 

 of acids derived from decaying vegetation. Why will limestone added 

 to such soils "sweeten" them. 



10. Soda mints consist largely of baking soda. Why may they be 

 taken to correct sour stomach ? 



