Question

The purest form of commercial iron is

• A. Scrap iron and pig iron
• B. Cast iron
• C. Wrought iron
• D. Pig iron

Answer 1

The correct option is C Wrought iron

1. Wrought Iron: It is a form of commercial iron having a very low carbon content (less than 0.10%), the impurities such as sulphur, phosphorus, silicon and manganese are less than 0.25%. It has the largest amount of pure iron in its constituents and is hence known as the purest form of commercial iron.
2. Cast Iron: It is a large family of ferrous alloys. These are multi-component ferrous alloys. The major constituents of cast iron are iron, carbon (2% or more), silicon (1% to 3%), minor elements (less than 0.1%) and often alloying elements (less than 0.1%). The common types of cast iron are (i) white cast iron, (ii) grey cast iron, (iii) ductile cast iron, and (iv) malleable cast iron.
3. Pig Iron: It is an iron-carbon alloy that has other elements such as silicon, manganese, sulphur, phosphorus. It has 3.5% to 4.5%, sulphur less than 0.05 % and phosphorus is up to 0.12%.
Therefore, wrought iron is the purest form of commercial iron. Hence, option (c) is the correct answer.