Which method is used for the refining of metals having low melting points?

$A$ solution of $CuSO_{4}$ was kept in an iron pot. After a few days,the iron pot was found to have a number of holes in it. Explain the reason in terms of reactivity. Write the equation of the reaction involved.

Which of the following is a noble metal?

State whether the following statement is true or false:
$A$ solution of an ionic compound in water contains ions,which move to the opposite electrodes when electricity is passed through the solution.

What is the molecular formula of cryolite?

Define alloys. List the properties of alloys that make them useful over pure metals. Explain this fact with suitable examples.