Question

Formula of Rust is

• A. \(Fe_2O_3 × H_2 O\)
• B. \(Fe_2O_4 × H_2 O\)
• C. \(Fe(OH)_2\)
• D. \(Fe(OH)_3\)

Answer 1

The Correct Option is A

Rust refers to the corrosion product formed as a result of the oxidation of iron. This happens when iron reacts with oxygen and water. The chemical formula typically associated with rust is \(Fe_2O_3 × H_2O\), which denotes hydrated iron(III) oxide. This particular formula captures one of the common hydrates formed during this oxidation process:

• Rust is chemically identified as hydrated iron(III) oxide, commonly expressed in its simplest form as \(Fe_2O_3 × H_2O\).
• When iron is exposed to moisture and oxygen over time, it forms rust in the reaction:
  \(4Fe + 3O_2 + 6H_2O \rightarrow 4Fe(OH)_3\) 
  Upon dehydration, \(Fe(OH)_3\) converts primarily into \(Fe_2O_3 × H_2O\).

From the given options, the correct formula for rust is \(Fe_2O_3 × H_2O\).

Answer 2

Correct answer: \(Fe_2O_3 \times H_2O\)
Explanation:
Rust is the reddish-brown substance formed on iron or steel due to the reaction with oxygen and moisture (water) in the environment. It is a hydrated form of iron(III) oxide, and its approximate chemical formula is:

\[ Fe_2O_3 \cdot H_2O \] This is not a fixed compound, but a general representation of rust.
Other options like \(Fe(OH)_2\) and \(Fe(OH)_3\) are iron hydroxides, not the actual rust formula.