The number of atoms in 0.1 mol of a triatomic gas is:

The correct option is B 1.806 x 10${}^{23}$
A number of atoms $=$ No. of moles x Avagadro's Number

$=0.1\times 6.022\times {10}^{23}$

$=6.02\times {10}^{22}$

Now since we have the number of molecules of the gas. And also we know that there are 3 atoms present in one molecule.

So the number of atoms present in 0.1 moles of the gas is:

$=3\times 6.02\times {10}^{22}$

$=18.06\times {10}^{22}$

$=1.806\times {10}^{23}$