explain electrochemical theory of rusting.class 12
Answers
Answer:
Mechanism of Rusting of Iron Electrochemical Theory of Rusting. ...
(i) Oxidation occurs at the anodes of each electrochemical cell. Therefore, at each anode neutral iron atoms are oxidised to ferrous ions. At anode : Thus, the metal atoms in the lattice pass into the solution as ions, leaving electrons on the metal itself
Answer:
When Fe is exposed to air, according to electro chemical theory, corrosion takes place due to formation of anodic and cathodic on the Fe surface.
At anode : Fe(s)⟶Fe
2+
(aq)+2e
−
H
2
O⟶H
+
(aq)+OH
(−)
(aq)
At cathode : 4H
+
+O
2
+4e
−
⟶2H
2
O
Fe
2+
ions are oxidized further by O
2
to form rust.
4Fe
2+
(aq)+O
2
(g)+4H
2
O⟶2FeO
3
+8H
+
∗ 1. By electropolating Fe with some non-corrosive metal such as Ni,Cr,Cu etc.
2. By coating reaction will be ;
Ni+Cu
2+
=Ni
2+
+Cu(n=2)
Nearest eqn :-
E
cell
=E
Cu
2+
/Cu
0
+E
Ni
2+
/Ni
0
−
2
0.059
log(
a
Cu
2+
a
Ni
2+
)
∴ E
cell
=0.34V−(−0.22V)−
2
0.059
log(
0.01
0.01
)
=0.66V