Question

I.When iron reacts with an oxygen an iron oxide compound with the formula $F{e_2}{O_3}$ can be formed.
II.Iron atoms form cations with a charge of \[ + 3\] by losing \[3\] electrons and oxygen atoms gain $2$ electrons to form an anion with a \[ - 2\] charge.
A.Statement I is true, statement II is true and is the correct explanation of phenomenon described in I.
B.Statement I is true, statement II is false.
C.Statement I is false, statement II is true.
D.Statement I is false, statement II is false.

Answer 1

Hint: To answer this question we will write the balanced chemical equation of iron with oxygen and also how they gain and lose electrons. As we know that ions are the group of atoms which have electric charge. We need to remember that the positive ions or cations are formed by loss of electrons and negative ions or anions are formed by gain of electrons. We must know that because of this gain and loss of electrons, the metals achieve electronic configuration of noble gas (i.e. octet rule last shell has full eight electrons).

Complete step by step answer:
When iron reacts with oxygen it forms iron oxide in the following way;
$4F{e_{\left( s \right)}} + 3{O_{2\left( g \right)}} \to 2F{e_2}{O_{3\left( g \right)}}$
In the above equation $Fe$ loses \[3\] electrons and gains \[ + 3\] and oxygen gains \[2\] electrons and achieves \[ - 2\] charge.
$Fe_{\left( s \right)}^0 \to F{e^{3 + }} + 3{e^ - }$ …….. (1)
$O_{\left( g \right)}^0 + 2{e^ - } \to 2{O^{2 - }}$ ……… (2)
On multiplying equation 1 with \[4\] and equation 2 with \[3\], we get,
$4F{e_{\left( s \right)}} \to 4F{e^{3 + }} + 12{e^ - }$
$6{O_{\left( g \right)}} + 12{e^ - } \to 6{O^{2 - }}$
Overall balanced equation is,
$4F{e_{\left( g \right)}} + 3{O_{2\left( g \right)}} \to 4F{e^{3 + }} + 6{O^{2 - }} \to F{e_2}{O_{3\left( g \right)}}$
So the correct answer is option A i.e. Statement 1 is true, statement 2 is true and is the correct explanation of the phenomenon described in 1.

Note:
We must have to remember that the $F{e_2}{O_3}$ is known as rust (hydrated iron oxide with the formula $F{e_2}{O_3}.x{H_2}O$ ) and formed when iron comes in contact with moisture in presence of oxygen and is reddish brown color. We must have to remember that the $F{e_2}{O_3}$ is known as pigment also and is used in the cosmetics industry. We know that iron keep changing its oxidation state from $ + 2$ to $ + 3$ and $ + 3$ to $ + 2$ and iron with $ + 3$ is most stable because it has half-filled ${d^5}$ orbitals as per Hund’s rule. Its main use is in the steel industry.