Where is iron found: Iron Rusting, Prevention, Ores, Uses, Physical and Chemical Properties

Have you ever taken notice of your surroundings? Like the cycle you ride, the engine of the car which you travel, and the benches where you sit. Have you ever wondered what material is present in them?

It is actually iron.

Iron objects have been found in Egypt dating from around 3500 BC. Iron is the fourth most abundant element, by mass, in the Earth’s crust. The core of the Earth is thought to be largely composed of iron with nickel and sulfur. The most common iron-containing ore is haematite (Fe₂O₃), but iron is found widely distributed in other minerals such as magnetite (Fe₃O₄) and siderite (FeCO₃) .

The first person to explain the various types of iron was René Antoine Ferchault de Réaumur who wrote a book on the subject in 1722. This explained how steel, wrought iron, and cast iron, were to be distinguished by the amount of charcoal (carbon) they contained.

Fun Fact. The Industrial Revolution which began around 18^th a century relied extensively on this metal.

Let us study this metal in much more detail.

Why do we study this concept?
Iron is a metal that is utilised frequently and is crucial to all living things. In terms of mass, iron is the most prevalent metal on Earth and makes up a sizeable amount of the planet's core and inner core. Due to its high reactivity, iron is only found naturally as iron ores in the Earth's crust. Learning about this crucial element is very enlightening and advantageous for long-term development.

Table of content:

Where is iron found?
Position in the periodic table
Physical properties of iron.
Chemical properties of iron.
Rusting of iron and its prevention
Ores of iron
Uses of iron
Practice problems
Frequently asked questions-FAQ

Where is iron found?

Iron is the fourth most prevalent element in the earth's crust, accounting for around 5% of its weight, and is thought to be the most important component in the planet's core. Iron is found in low amounts in the soil and is dissolved to a limited extent in groundwater and the ocean. Iron ores and minerals are numerous and widely distributed, although it is rarely encountered uncombined in nature except in meteorites.

Position in the periodic table:

Iron is a chemical element with the symbol Fe (from Latin: Ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. Its electronic configuration is
[Ar]3d⁶4s². Iron comes under the category of transition elements.

Physical properties of Iron:

Some of the important physical properties of Fe are high tensile strength, ductility, malleability, high thermal and electrical conductivity along with metallic lustre.

The number of protons in the nucleus of Fe i.e (atomic number) is 26
Iron (on the Periodic Table of Elements) has the atomic symbol Fe.
55.845 is the atomic weight of iron. (average mass of an atom)
Density of iron is about 7.874 gcm^-3.
Iron is a solid phase at room temperature i.e 298 K
Iron-56 is the most prevalent isotope (natural abundance: 91.754 per cent).
At room temperature, this metal is in the form of ferrite or α-form. At 910°C, it changes to γ-iron, which is much softer in nature.
It melts at 1536°C and boils at 2861°C.

Chemical properties of Iron:

1. Oxidation states:
Iron is usually found in +2 and +3 oxidation states. Ferrous refers to iron (II) compounds, while ferric refers to iron (III) compounds. The colour of iron (II) compounds is pale green, whereas iron (III) compounds are orange/brown.
It can also be found in a higher oxidation state of +6 in compounds like potassium ferrate (K₂FeO₄).

2. Reaction of Iron with Oxygen:
Iron is an extremely active metal that generates rust, or Fe₂O₃, when it reacts with oxygen and moisture in the air.
4Fe(s) + 3O₂(g) --> Fe₂O₃(s)

3. Reaction of Iron with Water:
Iron is metal that does not react with cold or hot water. However, when it comes into contact with steam, they produce metal oxide and hydrogen.
Below is the mentioned reaction:
3Fe(s) + 4H₂O(g) --> Fe₃O₄(s) + 4H₂(g)

4. Iron acting as Catalyst:

While Manufacturing ammonia from Haber’s process we use iron as a catalyst. In many complex organometallic reactions, Iron is used as a catalyst. Iron catalysts have the potential to cover all aspects of organic synthesis. The Fischer–Tropsch process, which converts virtually any carbonaceous material into liquid fuel, is also economically important.

(2n+1)H₂ (g) + n CO(g) --> C_nH_2n+2(l) + nH₂O (g) ↑
(2n) H₂ (g) + n CO(g) --> C_nH_2n(l) + nH₂O (g) ↑

Haber’s process reaction is shown below:

5. The reaction of iron with halogens:
Halogen reacts with iron to form ionic compounds.
For example, on gentle heating, chlorine reacts vigorously with iron to give chloride salt of iron.
3Cl₂(g) + 2Fe(s) --> 2FeCl₃(s) [dark brown]

Bromine reacts with iron to give a reddish-brown solid compound.
3Br₂(l) + 2Fe(s) --> 2FeBr₃(s) [Reddish brown]

6. The reaction of iron with acids:
Because iron is such an active metal, it can quickly displace hydrogen from mineral acid solutions. It produces iron(II) sulphate by reacting vigorously and exothermically with sulfuric acid.
Fe(s) + H₂SO₄(aq) --> FeSO₄(aq) + H₂(g) ↑

7. The reaction of iron with hydroxide ion:
Ferrous ions get precipitated by hydroxide ions.
Fe⁺²(aq) + 2OH^-(aq) --> Fe(OH)₂|(s) (white ppt)

8. The reaction of iron with phosphate
Phosphate ions does not precipitate Fe(II) but precipitate Fe(III) in acetic acid.
Fe³⁺(aq) + H₂PO^-4 --> (aq)FePO₄(s)| + 2H⁺(aq)

Rusting of Iron and its prevention:

Rusting is one of the changes that occur in iron objects, slowly destroying them. Because iron is needed to construct bridges, ships, automobiles, truck hulls, and a variety of other items, rusting results in significant financial losses. In fact, rusting is accelerated by high moisture content in the air.
The following equation can be used to represent the rusting process:

Iron (Fe) + Oxygen (O₂ , from the atmosphere) + water (H₂O) → RUST

How to prevent iron from rusting:
Prevent the contact of iron items with air, water, or both.

Applying a coat of paint or grease is one simple method. In reality, to avoid rust, these coats should be applied on a regular basis. Another option is to coat iron with a layer of chromium or zinc. Galvanisation is the process of putting a coating of zinc on iron. To avoid rusting, the iron pipes that carry water in our homes are galvanised.To make iron appear more lustrous (e.g., shiny) and to prevent corrosion electroplating can be done on the iron objects.

Ores of Iron:

Metallic iron can be recovered from iron ores, which are rocks and minerals. Massive hematite(Fe₂O₃), the most often mined iron ore, magnetite(Fe₃O₄), Siderite(FeCO₃), and Iron pyrites(FeS₂) are the four main types of iron ore deposits. The colours of these ores range from dark grey to bright yellow to deep purple to rusty red. The red colour of many of our rocks, as well as the deep red sands of Australia's deserts, is due to iron.
Goa has a huge amount of iron ore deposits.

Uses of Iron:

Metal iron rods are used to construct many buildings around the world.
Home appliances such as plates, pans, utensils, dishwashers, and cooking stoves are all made of this metal. Iron is preferred because it is readily available.
It helps in oxygen transfer throughout the body. It's one of haemoglobin's most critical components.
Magnets are made from iron. Iron, often known as magnetite, is a naturally occurring permanent magnet.
Smelting was the primary use of iron ore. Iron is being employed to create powerful cutting tools and other equipment. Iron was used to make early tools such as hammers, knives, and swords.

Practice problems:

Q1. What are stainless steels?
Answer: Stainless steel is formed by combining iron, carbon, and metals such as chromium, nickel, and manganese with other elements. It is rust-free.

Q2. What is the oxidation state of iron in Fe₂O₃?
A. +2
B. +3
C. +2
D. 0
Answer: B
Solution: Let us assume the oxidation state of Fe in Fe₂O₃ be x. The oxidation state of oxygen is -2 because it in oxide form. Solving this,
2x + ( - 2) × 3 = 0
=> 2x - 6 = 0
=> x = + 3

Hence, +3 is the oxidation state of Fe in Fe₂O₃

Q3. __________ is the purest form of iron.

A. Grey cast iron
B. Brown cast iron
C. Wrought iron
D. White cast iron

Answer: C
Solution: Iron content present in wrought iron is 99.9%. Hence, wrought iron is the purest form of iron.

Q4. The metal present in haemoglobin is

A. Mg
B. Co
C. Na
D. Fe

Answer: D
Solution: The heme group (a component of the haemoglobin protein) is a metal complex that can bind or release molecular oxygen, with iron as the core metal atom. So the correct answer comes out to be Fe.

Frequently asked questions- FAQ

Question 1. How much iron intake is needed by an adult per day?
Solution: The needed iron intake is around 1 mg per day and is based on daily iron losses through faeces, urine, and sweat. During menstruation, women also lose blood. The amount of iron required during growth and pregnancy is increased.

Question 2. Which food contains rich sources of iron?
Solution: Beetroot, lentils, and wholemeal cereals are examples of plant-based foods that are high in iron.

Question 3. What are the symptoms if a person is suffering from iron deficiency?
Solution: Inflammation of the corners of the mouth, an increased risk of heart illness, altered hair and nail growth, and cracked, dry, and rough skin are the most common symptoms. Iron deficiency anaemia is the most serious type.

Question 4. From where we get the symbol of iron as Fe?
Solution: Iron's Latin name is Ferrum, which is also the source of its atomic symbol, Fe.

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