Non-metals form two types of oxides. Choose these two types from the following oxides:
$SO_2, NO_2, CO, H_2O, N_2O$

State reasons for the following:
$(i)$ Metals are good conductors of heat.
$(ii)$ Addition of some silver to pure gold for making ornaments.
$(iii)$ Inability of non-metals to displace hydrogen from dilute sulphuric acid.

What is German silver?

What happens when:
$(i)$ $A$ piece of calcium is dropped in water.
$(ii)$ Sodium is kept exposed in air.
$(iii)$ Iron nail is dipped in copper sulphate solution.
$(iv)$ Potassium is dropped in cold water.
$(v)$ Carbon dioxide is compressed in water at high pressure.
Give chemical equations involved in all the above reactions and balance them.

Which one of the following figures correctly describes the process of electrolytic refining?

What are the constituent elements of stainless steel?