Iron(II) sulfate Formula – Structure, Properties, Uses, Sample Questions

Iron is a chemical element with the symbol Fe (Latin: from Ferrum) and atomic number 26. This is the first transition series of the periodic table and the metal belonging to group 8.  Iron is an element usually found in the form of a hard, dark gray metal. Used in the manufacture of steel, it is also a component of many tools, buildings, and vehicles. Very little iron is found in blood and diet. A huge iron gate has been locked.

Sulfate is a  compound composed of sulfur and oxygen atoms. It is one of the most common compounds available as a naturally occurring mineral on earth. It is found throughout the environment primarily through atmospheric and terrestrial processes. The main causes of sulfate are rocks and minerals containing sulfides, sulfur released by erosion of evaporite deposits, and even volcanoes. Sulfates are derivatives of salts that contain various elements such as potassium, sodium, calcium, magnesium, and barium.

Iron(II) sulfate is an iron salt also known as green vitriol. Iron sulfate refers to various salts of the formula FeSO4 · xH2O. Other names for ferrous sulfate are Iron sulfate, green vitriol, iron vitriol, copper, melanterite, and Szomolno kit. Blue-green heptahydrate (a hydrate containing a “7” water molecule) is the most common type of this material. All ferrous sulfate dissolves in water to form the same aqua complex [Fe(H₂O)₆]²⁺. It is paramagnetic and has an octahedral molecular structure. The term copper dates back to the time when copper (II) sulfate was known as blue copper. In contrast, ferrous sulfate and zinc sulfate were known as green and white copper. Formed when the iron file mixes with the copper sulfate solution, the iron pushes out the copper. This is because copper is more reactive and leads to the formation of ferrous sulfate.   It is on the World Health Organization’s list of essential medicines as the safest and most effective medicine needed in the medical field.

Structure of Iron (II) sulfate

Iron(ii) Sulfate

Production of  Iron (II) Sulfate

• Sulfuric acid pickling baths are used to polish steel sheets or bars prior to plating or coating. A significant amount of ferrous sulfate is formed as a by-product.

Fe + H₂SO₄ ⟶ FeSO₄ + H₂

Another source of large quantities is the sulfate process that produces titanium dioxide from ilmenite.

• Oxidation of pyrite produces ferrous sulfate, which can also be produced economically. 

2FeS₂ + 7O₂ + 2H₂O ⟶ 2FeSO₄ + 2H₂SO₄

• Ferrous sulfate can be produced by removing less reactive metals than iron from the sulfate solution. 

CuSO₄+Fe ⟶ FeSO₄+Cu

Physical Properties of Iron (II) Sulfate or Ferrous Sulfate

• Molar Mass of Anhydrous ferrous sulfate is 151.91 g/mol
• Colour It is White crystals ( in Anhydrous form)
• Melting point is 56°C – 64°C
• Boiling point greater than 300°C
• Solubility: It is soluble in water

Chemical Properties of Iron (II) Sulfate or Ferrous Sulfate

• When Ferrous sulfate reacts with aluminum and forms aluminum sulfate and metallic iron, which is a displacement reaction. The reaction is given as-

2Al + 3FeSO₄ → Al₂(SO₄)₃ + 3Fe

• In the presence of sulphuric acid, Ferrous sulfate reacts with potassium permanganate it forms ferric sulfate, manganese sulfate, potassium sulfate, and water. The reaction is given as-

10FeSO₄ + 2KMnO₄ + 8H₂SO₄ → 5Fe₂(SO₄)₃ + 2MnSO₄ + 8H₂O + K₂SO₄

• When ferrous sulfate is heated, the water of crystallization is first lost and then the actual green crystals turn into white anhydrous solids. Upon further heating, the anhydrous solid emits white smoke of sulfur trioxide and sulfur dioxide, leaving a reddish-brown iron oxide. Iron sulfate begins to decompose at approximately 680 ° C (1,256 ° F).

2 FeSO₄ → Fe₂O₃ + SO₂ + SO₃

Uses of  Iron (II) Sulfate

Commercial Use

• Industrially, ferrous sulfate is primarily useful as a precursor to other iron compounds. 
• It is a reducing agent and is also used to reduce chromate in cement to less toxic Cr (III) substances.
• Ferrous sulfate has been used as a dye fixative in the textile industry for centuries to blacken the leather and as a source of ink. The treatment of sulfuric acid by distillation of green vitriol (iron (II) sulfate) is a process that has been known for over 700 years.

Medicinal Use

• Iron is an essential heavy metal useful in some multivitamin and mineral supplements. 
• Iron is also used therapeutically at high doses to treat or prevent iron deficiency anemia. 
• Iron has little or no adverse effect on the liver when taken in the usual prescribed daily or supplemental doses. At high doses and intentional or accidental overdose, iron causes severe toxicity, one of the causes of which is acute liver failure. 
• Iron fumarate, ferrous gluconate, and ferrous sulfate are the most common oral iron supplements. Iron Sulfate is the safest and cheapest supplement for iron.
• Green vitriol is also a useful reagent for detecting fungi.  
• Useful as an iron catalytic element for Fenton’s reagent.  
• It is one of the most important ingredients of gall ink.
• It is used to purify water by agglomeration and to remove phosphate in urban and industrial sewage treatment plants to avoid eutrophication of water bodies.

Sample Questions

Question 1: What are the benefits of ferrous sulfate?  

Solution:

Myoglobin allows the storage of oxygen in muscle cells. Iron sulfate is an essential mineral for the body. Iron sulfate helps treat iron deficiency anemia, a red blood cell deficiency caused by low iron levels in the body. It may also be useful for applications other than those listed here.   

Question 2: Why is iron called ferrous?  

Solution:

“Ferrous” usually means “iron” and its expression comes from the Latin word Ferrum (“iron”). Iron metals include steel and pig iron (with a few percent carbon contents), and iron alloys with many other metals (such as stainless steel)

Question 3: What are the side effects of an overdose of ferrous sulfate?  

Solution:

The most commonly reported side effects include various types of gastrointestinal symptoms such as nausea, diarrhea, vomiting, abdominal pain, constipation, and black or decolored stools.

Question 4: How useful is iron sulfate and where can it be used? 

Solution:

Iron ferrous sulfate has proven to be a very useful chemical as it is used in a variety of ways, including iron supplements for people suffering from iron deficiency. It is also used to treat anemia caused by iron deficiency. Iron sulfate can also be used for chlorination, known as copper chlorination.   

Question 5: What are the main differences between ferrous and ferric?  

Solution:

Iron has several values. Determined as ferric or ferrous, depending on the number of electrons lost. When an iron atom loses three electrons, it gains a +3 charge and functions as an iron ion (Fe⁺³). When an iron atom loses two electrons, it gains a +2 charge and functions as an iron ion (Fe⁺²). The electron configuration of ferrous ions is 3s²3p⁶3d⁶, and the electron configuration of ferric ions is 3s²3p⁶3d⁵. According to Hund’s law of multiplicity, ferric ions are half-filled and therefore more stable than ferrous ions. Examples of ferrous compounds: FeO and Examples of ferric compounds: FeCl₃.

Question 6: What form of iron is better absorbed?

Solution:

Heme iron is easy to consume and is an important source of iron for people with and without heme chromatolysis. Non-heme iron usually does not run out faster than heme iron.

Question 7: What color is the ferrous sulfate crystal? How does this color change after heating?  

Solution:

The crystals of ferrous sulfate are green.

The water molecule is contained in iron sulfate crystals (FeSO₄・7H₂O). When ferrous sulfate crystals are heated, they lose water and form anhydrous ferrous sulfate (FeSO₄). This will change the color from light green to white.