Question

Mark the variety of iron which has the highest melting point.
A.Pig iron
B.Cast iron
C.Steel
D.Wrought iron

Answer 1

Hint: Magnetite, haematite, Goethite, and limonite or siderite are various sorts of minerals of iron. The iron is typically found as magnetite which has ${ 72.4 }$% iron, hematite with ${ 69.9 }$% iron, goethite with ${ 62.9 }$% iron, limonite, or siderite with ${ 48.2 }$% iron.

 Complete answer:
1. Pig iron is a transitional result of the iron business, otherwise called unrefined iron, which is obtained by purifying iron minerals in an impact heater. It contains about 95% Fe, 4% C any varying quantities of other impurities, which makes it exceptionally fragile and not helpful straightforwardly as a material aside from restricted applications. The melting point of pig iron is ${ 1000-1200 }$ degrees celsius.
2. Cast iron: Cast iron can be acquired by emptying pig iron straightforwardly into molds of the ideal shape. Cast iron is hard and weak and can be utilized where it won't be exposed to mechanical or warm shock. Cast iron is a gathering of iron-carbon compounds with a carbon content of more than 2%. Its convenience gets from its generally low softening temperature. The composite constituents influence its shading when broken: white cast iron has carbide debasements that permit splits to go straight through. The melting point of cast iron is approximate ${ 1127-1204 }$ degrees celsius.
3. Steel: Steel is a compound of iron with commonly a couple of percent of carbon to improve its quality and crack opposition contrasted with iron. Numerous other extra components might be available or included. Treated steels that are consumption and oxidation safe need regularly an extra 11% chromium. On account of its high rigidity and ease, steel is utilized in structures, framework, apparatuses, ships, trains, vehicles, machines, electrical apparatuses, and weapons.
The melting point of steel is almost ${ 1300-1400 }$ degrees celsius.
4. Wrought iron: Wrought iron is an iron combined with a low carbon content (under 0.08%) rather than that of cast iron (2.1% to 4%). It is a semi-combined mass of iron with fibrous slag considerations (up to 2% by weight), which gives it a "grain" looking like wood that is noticeable when it is carved or twisted to the point of failure. Today, wrought iron is chiefly utilized for fancy purposes. It is frequently used to make metal doors, iron railings, garden furniture, garage entryways, and other improving ironwork for the outside showcase.
The melting point of wrought iron is ${ 1540 }$ degrees celsius.
As we see wrought iron has the highest melting point in the varieties of iron.

 Hence, the correct option is D.

 Note:
Melting point of the variety of iron depends on many factors. Ideally it depends on the intermolecular force of attraction. But sometimes the presence of impurities also increases the melting point of the substance. In case of alloys it depends on the constituents of the alloy.