Question

Which of the statements about the reaction below are incorrect?
$\text{2Pb}{{\text{O}}_{\left( \text{s} \right)}}\text{ + }{{\text{C}}_{\left( \text{s} \right)}}\text{ }\to \text{ 2P}{{\text{b}}_{\left( \text{s} \right)}}\text{ + C}{{\text{O}}_{2\left( \text{g} \right)}}$
(a) Lead is getting reduced
(b) Carbon dioxide is getting oxidised
(c) Carbon is getting oxidised
(d) Lead oxide is getting reduced.
A. (a) and (b)
B. (a) and (c)
C. (a), (b) and (c)
D. All

Answer 1

Hint: Oxidation reactions are those reactions in which the gain of oxygen and loss of electron as well as hydrogen take place whereas reduction reaction is those reactions in which the gain of hydrogen and electron & loss of oxygen take place.

Complete Solution:
-In the given reaction lead oxide reacts with the carbon to form lead and carbon dioxide.
-There are three methods through which we can identify which molecule is oxidised and which molecule is reduced.
-One by calculating the oxidation number, second by identifying which molecule has lost oxygen and who gains it and third is by identifying the no. of electrons.
-So, in the lead oxide, the lead has formed lead by losing a molecule of oxygen whereas carbon has formed carbon dioxide by gaining the oxygen molecule.
-This shows that lead oxide has been reduced to the lead and carbon has been oxidised to carbon dioxide.
-Moreover, the oxidation state of lead from reactant to product decreases from +2 to 0 whereas the oxidation state of carbon from reactant to a product increases from 0 to +4.
The oxidation state of lead in $PbO$ will be:
$x - 2 = 0$
$x = +2$
The oxidation state of lead in Pb will be 0, because it is in a free state.

- The oxidation state of carbon in C will be 0, because it is in a free state.
The oxidation state of carbon in $C{{O}_{2}}$ will be:
$x + 2(-2) = 0$
$x - 4 = 0$
$x = +4$
-So, option (c) and (d) are the correct answers whereas option (a) and (b) are the incorrect answer.

So, the correct answer is “Option A”.

Note: The oxidation state increases when there is a loss of electron that's why in oxidation reaction the loss of electron takes place and the oxidation state decreases when there is a gain of an electron that's why in reduction reaction the gain of electron takes place.