I’m unsure why people are complicating matters with Avogadro’s number. You have a number of moles and the question asks a number of moles. There’s no point in converting to an exact number of atoms at all.
1.5 moles of H2SO4 means you have 1.5 moles of this molecule.
The molecule has 7 atoms in it for each molecule.
So if you have 1.5 moles of the molecule, you have 7*1.5 = 10.5 moles of atoms in those molecules.
