(a) What is rust? Give the equation for the information of rust.
(b) State two conditions necessary for rusting of iron?
(c) How does the painting of an iron object prevent rusting?
(a) What is rust? Give the equation for the information of rust.
(b) State two conditions necessary for rusting of iron?
(c) How does the painting of an iron object prevent rusting?
a). Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture.
The reaction of Rust formation:
4Fe+3O2⟶2Fe2O3
Rust, that chemical substance that is responsible for the felling of bridges, the sinking of ships, the loss of metallic and electrical conducting properties of metals, has the general chemical formula Fe2O3.nH2O
An above formula is a dehydrated form of iron(III) hydroxide.
Now, a little summary of its chemistry.
Rusting is an electrochemical process which requires the presence of water, oxygen, and an electrolyte.
General chemistry texts provide details. But, for the sake of the question, I would show an overall formula for the formation of that reddish-brown crud we call rust:
4Fe(s)+6H2O(l)+3O2(g)⟶Fe(OH)3(s)
On dehydration, the iron(III)hydroxide produces Fe2O3.H2O, what we commonly call rust.
b). Conditions for Rusting of Iron
- The presence of water and oxygen is essential for the rusting of iron.
- Impurities in the iron, the presence of water vapor, acids, salts and carbon dioxide hastens rusting.
- Pure iron does not rust in dry and carbon dioxide free air. It also does not rust in pure water, free from dissolved salts.
- Metals like chromium, zinc and magnesium prevent rusting to a great extent and alkalis also help to prevent rustin
c). Paint or plating(like chrome plating) prevents the H2O molecules from reaching the surface of the metal so it can't get the oxygen.
a). Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture.
The reaction of Rust formation:
4Fe+3O2⟶2Fe2O3
Rust, that chemical substance that is responsible for the felling of bridges, the sinking of ships, the loss of metallic and electrical conducting properties of metals, has the general chemical formula Fe2O3.nH2O
An above formula is a dehydrated form of iron(III) hydroxide.
Now, a little summary of its chemistry.
Rusting is an electrochemical process which requires the presence of water, oxygen, and an electrolyte.
General chemistry texts provide details. But, for the sake of the question, I would show an overall formula for the formation of that reddish-brown crud we call rust:
4Fe(s)+6H2O(l)+3O2(g)⟶Fe(OH)3(s)
On dehydration, the iron(III)hydroxide produces Fe2O3.H2O, what we commonly call rust.
b). Conditions for Rusting of Iron
- The presence of water and oxygen is essential for the rusting of iron.
- Impurities in the iron, the presence of water vapor, acids, salts and carbon dioxide hastens rusting.
- Pure iron does not rust in dry and carbon dioxide free air. It also does not rust in pure water, free from dissolved salts.
- Metals like chromium, zinc and magnesium prevent rusting to a great extent and alkalis also help to prevent rustin
c). Paint or plating(like chrome plating) prevents the H2O molecules from reaching the surface of the metal so it can't get the oxygen.
