I hope this is in the right section.
2h2+o2<-->2h20

so the question is how many hydrogen atoms are there in h2 according to the equation above.

is this right 2mol h2 * (6.022*10^23 molecules h2)/(1 mol h2) *(2 atoms H/ 1 molecule of h2)

or
4 mol H*( 6.022*10^23 atoms H/1mol H)
my teacher did a similar question only difference was his was how many hydrogen gas molecules are there, so he did 2 mols l* avogadro.

yes you are right
No of atoms of H =  2mol of H2  X 2 mol of H atoms / 1 mol of H2    X avogadro's number / 1 mole of H atoms
                    2 X 2 X 6.022 X 10^ 23
          =    4 X 6.022 X 10^ 23 no of atoms