Calculate the concentration of iron in the sample in parts per million.

1.  A 0.9882 gram sample of iron ore is dissolved, the iron reduced to Fe2+, and the solution was titrated with 36.40 mL of 0.02065 M KMnO4 in acid solution. (a)  Write the titration reaction.  (b)  Calculate the %FeO (M.M. = 71.85) in the sample.   2.  A sample of primary standard grade K2Cr2O7 (MM = 294.20) weighing 0.2153 g is dissolved, the solution acidified and excess KI added. The liberated I2 requires 44.86 mL of the Na2S2O3 for titration. (a)  Write the titration reaction.  (b)  Calculate the molarity of the titrant solution.    Box the final answer.

Hh.88.

A sample of alfalfa meal weighing 2.0 g is analyzed by Kjeldahl method for the percentage of nitrogen. The liberated NH3 is caught in a solution of H3BO3, and 8.23 ml of HCl are required in the subsequent titration. A sample of pure (NH4)2SO4 (132.12) weighing 0.61 g is treated with excess NaOH and the liberated NH3 (17.04) is also caught in H3BO3. The resulting solution requires 20 ml of the acid for titration. Calculate the percentage of protein in the sample using 6.25 as the factor.