The CO in a 20.3 L sample of gas was converted to CO2 by passing the gas over iodine pentoxide heated to 150° C :

${\mathrm{I}}_2{\mathrm{O}}_5\left(\mathrm{s}\right)+5\mathrm{CO}\left(\mathrm{g}\right)⟶5{\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{I}}_2\left(\mathrm{g}\right)$

The iodine distilled at this temperature and was collected in an absorber containing 8.25 mL of 0.01101 $\mathrm{M}$ ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3$ . The excess hypo was back-titrated with 2.16 mL of 0.00947 MI 2 solution. The milligrams of CO in 1L of the original gas sample was therefore :