1.0 mole of CO2 contains :

Correct option is A

Step 1

One mole of CO2 contains 6.02 x 1023 molecules of CO2 (by definition of a mole).

Step 2

Each molecule of CO2 contains 1 carbon atom and 2 oxygen atoms.

Step 3

Therefore, one mole of CO2 contains 6.02 x 1023 carbon atoms and 2×6.02 x 1023=1.204× 1024 oxygen atoms.

Step 4 

The concept of gram atoms is not applicable in this context. The correct statements are:

(a) 6.02 x 1023 atoms of C