Generally,non-metals are not conductors of electricity. Which of the following is a good conductor of electricity?

Which of the following metals are obtained by electrolysis of their chlorides in molten state?
$(i)$ $Na$
$(ii)$ $Ca$
$(iii)$ $Fe$
$(iv)$ $Cu$

Solder is an alloy of lead and tin. It has a:

What is the ratio of dihydrogen gas to dinitrogen gas used in the production of ammonia gas by Haber's process?

What happens to potassium and sodium if they are kept in the open? Why are they immersed in kerosene?

Give a reason to explain:
$(i)$ Why do aluminium sheets not corrode easily?
$(ii)$ Why is a copper vessel covered with a green coating in the rainy season?