LEAD AND TIN 509 



Exercises. 1. Make equations for: (a) the action of air and 

 water on lead to form the hydroxide; (b) the precipitation of lead 

 chromate by adding K 2 Cr0 4 to lead nitrate solution; (c) the action 

 of hydrogen sulphide on white lead; (d) the precipitation of 

 PbCl 2 and of PbI 2 . 



2. Tin melts at 232 and lead at 326. Solder (1 : 1) melts 

 (and solidifies) at 210. Why is this? What is the advantage of 

 using solder? 



3. Make equations for: (a) the action of soda on solutions of 

 stannous and stannic chlorides, respectively: (b) the action of 

 hydrogen sulphide on the same salts. 





