How many moles of K2Cr2O7 can be reduced by 1 mol of Sn2+?

Cr2O72−+14H++6e−→2Cr3++7H2OSn2+→Sn4++2e−×3---------------------------------------------------------Cr2O72−+14H++3Sn2+→3Sn4++2Cr3++7H2OIt is clear from this equation that 3 mol of Sn2+ reduces 1 mol of Cr2O72− , hence 1 mol of Sn2+ will reduce 13 mol of Cr2O72−