Consider a titration of potassium dichromate solution with acidified Mohr's salt solution using diphenylamine as indicator. The number of moles of Mohr's salt required per mole of dichromate is

6Fe2++Cr2O72-+14H+⟶6Fe3++2Cr3++7H2O                      Cr2O72-⟶2Cr3+x-factor = 6 Mohr's salts FeSO4·NH42SO4·6H2O Oxidation, Fe2+⟶Fe3+x-factor = l mole ratio is reverse of x-factor ratio.Therefore, one mole of dichromate required = 6moles of Mohr's salt.