Part II 

 (Omit one group. Each question counts 10.) 

 Group A 



6. Arrange three metals in the order of decreasing activity. Describe in detail 

 three experimental methods by which the correctness of the suggested order 

 may be proved. 



J. (a) State the physical and chemical characteristics of chlorine, bromine, and 

 iodine as regards: physical state, color, solubility, tendency to combine 

 with hydrogen. 



(b) How may bleaching powder be made ? What are its properties ? 



Group B 



8. (a) What weight of sulphur dioxide will occupy a volume equal to that of 



42 grams of nitrogen at the same temperature and pressure ? (Atomic 

 weights: S32, 016, N14.) 



(6) What volume of a solution of hydrochloric acid containing 73 grams per 

 liter would suffice for the exact neutralization of the sodium hydroxide 

 obtained by allowing . 46 gram of metallic sodium to act upon water ? 

 (Atomic weights: CI 35.5, Na 23, O 16, H 1.) 



9. {a) What is a reversible reaction ? Illustrate by means of an equation. 

 {h) Under what three conditions will a reaction go to completion ? 



(c) On the basis of the electrolytic dissociation theory, how would you 



explain (1) the neutralization of an acid by a base? (2) the changes 

 that take place when a solution of copper sulphate is electrolyzed 

 between copper electrodes ? 



Group C 



10. {a) What substance burns with a blue flame on the top of a coal fire ? Write 



two equations for the reactions involved in the formation of this sub- 

 stance; write an equation for the reaction involved in its combustion. 



(6) Define the term "by-product." Show how a valuable by-product is 

 obtained in some chemical process of commercial importance. 



11. Considering each of the following substances separately, name two impor- 



tant products made from it directly or by admixture or reaction with other 

 substances: (a) lime, {b) salt, (c) crude petroleum, {d) coke, {e) sand. 



3* 



