hello there !!
In the Question it's asked that total atoms present in 0.1 mol of H2So4.
so , in the question number of moles is given as 0.1 mole
=> n = 0.1 mole
and total atoms present are = ???
So , in H2So4 molecule there are two hydrogen atoms
=> H2So4 → 2 hydrogen atoms
one mole of H2So4 consist of ;
=> 2 × 6.022 × 10²³
1 mol = 6.022 × 10 ²³ atoms
Therefore, 0.1 mole of H2So4
=> 0.1 × 2 × 6.022 × 10²³ Atoms
=> 0.1 × 2 × 6.022 × 10²³ Atoms=> 12.004 × 10²² Atoms