One mole of ${C{O_2}}$ contains?
(A). $6.02\times {{10} ^ {23}} $ atoms of oxygen
(B). $6.02\times {{10} ^ {23}} $ atoms of carbon
(C). $18.10\times {{10} ^ {23}} $ molecules of ${C{O_2}}$
(D) $3$g atoms of ${C{O_2}}$

- Hint: In the question we have to answer that one mole of CO2 contains how many entities just like one dozen bananas contains how many bananas.

Complete step by step answer:
Let’s dive into mole,
We know that one mole is the amount of a substance that contains as many particles or entities as there are in exactly $12$ g of the 12C isotope.
   i.e. one mole of any element (or $1$ g atom) = $6.02\times {{10} ^ {23}} $ atoms.
Now, in the question the given compound CO2 there are two oxygen atoms and one carbon atom. Therefore, one mole of CO2 contains one mole of carbon and two moles of oxygen.
   $1$ mole of CO2 = $1$ mole of C = $6.02\times {{10} ^ {23}} $ atoms of carbon.
   $1$ mole of CO2 = $2$ mole of O = $2\times 6.02\times {{10} ^ {23}} $ = $12.04\times {{10} ^ {23}} $ atoms of oxygen.
But according to definition of mole,
   $1$ mole of CO2 = $6.02\times {{10} ^ {23}} $ molecules of CO2
Therefore, options (b) is correct.

Note: Here $6.02\times {{10} ^ {23}} $ is known as Avogadro’s number (NA). It represents us the number of atoms/molecules/entities present in one mole of a substance. The mole concept is a bit confusing for most students , so I recommend that please read it carefully and as many times as you can. Also try to compare it with daily measurements.