Option a: Mond's process is used for purification of Ni
Vapour Phase Refining
Step 1:
Ni is heated in stream of CO to form nickel tetracarbonyl
Ni+4CO330−350K−−−−−−→Ni(CO)4Volatile
Step2:
Volatile compound is subjected to higher temperature
Ni(CO)4450−470K−−−−−−→NiPure metal+4CO
Option 2: The iron obtained from the Blast furnace contains about 4% carbon and many impurities in smaller amounts (e.g., S,P,Si,Mn). This is known as pig iron. It can be moulded into a variety of shapes.
Option 3: Wrought iron is pure iron with 0.1% carbon.
Option 4: The solid copper obtained has blistered appearance due to evolution of SO2. This copper is called blister copper.