Answer: The empirical formula of the compound is 
Explanation:
Empirical formula is defined formula which is simplest integer ratio of number of atoms of different elements present in the compound.
Percentage of iron in a compound = 36.76 %
Percentage of sulfur in a compound = 21.11 %
Percentage of oxygen in a compound = 42.13 %
Consider in 100 g of the compound:
Mass of iron in 100 g of compound = 36.76 g
Mass of iron in 100 g of compound = 21.11 g
Mass of iron in 100 g of compound = 42.13 g
Now calculate the number of moles each element:
Moles of iron=
Moles of sulfur=
Moles of oxygen=
Divide the moles of each element by the smallest number of moles to calculated the ratio of the elements to each other
For Iron element = 
For sulfur element =
For oxygen element = 
So, the empirical formula of the compound is 
0.355M x 0.0282L= 0.01 moles of H2SO4. Remember sulphuric acid is diprotic so it will release 2 from each molecule.
<span>So moles of protons = 0.01 x 2 = 0.02 moles of H+ </span>
<span>For neutralization: moles H+ = moles OH- </span>
<span>Therefore moles of NaOH = 0.02 </span>
<span>conc = moles / volume </span>
<span>Conc NaOH = 0.02 / 0.025L = 0.8M </span>
Tarnish is Ag2S-silver sulfide and the oxidation state of silver is +1
Well, first we must remember that

This is because


So then
