Question

n- factor of $C{O_2}$ formed when calcium carbonate is heated is:
A. zero
B. 1
C. 2
D. 3

Answer 1

Hint:The number of electrons transferred throughout the reaction from the reactant side to the product side is known as the n- factor. For an acid n- factor is the number of \[{H^ + }\] ions replaced by one mole of an acid. For a base, n- factor is the number of $O{H^ - }$ ions replaced by one mole of a base.

Complete step by step answer:
As it is known, the n- factor is defined as the number of electrons transferred throughout the system or the number of electrons lost or gained by the system and the difference in the oxidation states of the compounds. When calcium carbonate (\[CaC{O_3}\] ) is thermally decomposed, it produces calcium oxide and carbon dioxide. Let us write the particular chemical equation for the calcination process (Heating in absence of air) of calcium carbonate.
$CaC{O_3}\xrightarrow{\Delta }CaO + C{O_2}$
From the above reaction, let us find the oxidation state of the carbon atom in calcium carbonate and carbon dioxide.
(i) $CaC{O_3}$ : Let the oxidation state of the carbon atom be $x$ .
The oxidation state of calcium atom = $ + 2$
The oxidation state of oxygen atom = $ - 2$
Thus, determining the equation of oxidation state, we have:
$ + 2 + x + 3( - 2) = 0$
$ \Rightarrow x = 6 - 2 = + 4$
Thus, the carbon atom in calcium carbonate has an oxidation state = $ + 4$ .
(ii) $C{O_2}$ : Let the oxidation state of carbon atom be $y$ .
The oxidation state of calcium atom = $ + 2$
The oxidation state of oxygen atom = $ - 2$
Thus, determining the equation of oxidation state, we have:
$y + 2( - 2) = 0$
$ \Rightarrow y = + 4$
Thus, the carbon atom in carbon dioxide has an oxidation state = $ + 4$ .
As we can clearly see that there is no change in the oxidation state of the carbon atom, this means that n- factor is equal to zero.
Thus, the correct option is A. zero.


Note:If an atom with high oxidation state gains electrons, its oxidation state decreases and the amount by which it decreases is the n- factor. If an atom with a certain oxidation state loses electrons, its oxidation state increases and the amount by which it increases is the n- factor.