QUESTIONS AND PROBLEMS 117 



QUESTIONS AND PROBLEMS FOR REVISION AND 

 EXAMINATION. 



Basic Oxides, Acid Oxides, and Salts. 



1. How are the oxides of magnesium and potassium distinguished from 



the oxides of phosphorus and sulphur ? 



2. What happens when a sokition of a basic oxide is exactly neutralised 



by a solution of an acidic oxide ? Give examples. 



3. Define a basic oxide, an acidic oxide, and a salt, and give examples 



of each of these classes of chemical compounds. 



4. Give a method of distinguishing a metallic from a non-metallic 



element. 



5. Is the element hydrogen a metal or a non-metal ? Upon what fact 



do you base your answer ? 

 *6. Of the three powders, identify the acidic oxide, the basic oxide, and 

 the salt. (Silica, magnesia, and gypsum.) 



Chemical Properties of the Metals : The Metallic Oxides. 



7. State two methods which may be employed to study the oxidisability 



of the metals. 



8. Compare the action of air in the cold on sodium, potassium, 



magnesium, zinc, iron, copper, and mercury. Why does iron 

 corrode so much more than zinc ? What are tinned and gal- 

 vanised iron? 



9. Describe fully the action of sodium and potassium on water, giving 



the products of the reaction. In what respect does the action of 

 sodium differ from that of potassium, and what does this teach as 

 to the relative attraction of these two elements for oxygen ? 



10. State what are the colours imparted to a non-luminous flame by the 



incandescent vapours of sodium, potassium, calcium, strontium, 

 and barium compounds. When the colour of potassium vapour is 

 masked by that of sodium, how should the flame be viewed to 

 render the former colour visible ? 



11. Explain the use of the spectroscope for identifying the incandescent 



vapours of metals. 



12. If in their oxidisability, calcium, barium, and strontium are inter- 



mediate between sodium and magnesium, what should be their 

 behaviour towards air and water ? 



13. State whether magnesium, zinc, and iron are combustible, and under 



what conditions (if any) they attack water. Describe the experi- 

 ments made upon the subject. 



