Abbreviation of ZS

Abbreviation of ZS:

Zoological Society

What are the constituents of solder alloy? Which property of solder makes it suitable for welding electrical wires?
Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), treated with HNO3, hydrogen is not liberated, why?
Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them?
What type of oxides are formed when non-metals combine with oxygen?
In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte ?