One mole of triatomic gas and three moles of a monoatomic gas contain same number of atoms.

The correct option is A True

Mole concept

• The mole concept is defined as a convenient method to express the number of substances.
• The elementary entities that can be represented in moles can be atoms, molecules, monoatomic or polyatomic ions, and other particles
• The number of moles of a substance can be calculated as

$n=\frac{N}{N_a}(N=No.ofelementaryentity,N_A=Avagadronumber)$

• Therefore, the number of particles can be calculated as

$N=nX{N}_{A}XAtomicity$

• In 1 mole of triatomic gas, N: (atomicity=3)(no. of moles=1)

$$\begin{gathered} N=1x6.022x{10}^{23}x3 \\ =18.066x{10}^{23} \end{gathered}$$

• In 3 mole of monoatomic gas, N: (atomocity=1)(no. of moles=3)

$$\begin{gathered} N=3x6.022x{10}^{23}x1 \\ =18.066x{10}^{23} \end{gathered}$$

Hence, the given statement is True i.e., One mole of triatomic gas and three moles of a monoatomic gas contain the same number of atoms.