Final answer:
Without the balanced chemical equation and additional information about the reaction, it is not possible to accurately determine the mass of potassium oxalate monohydrate that reacted with ferric chloride.
Step-by-step explanation:
The question being asked about the mass of potassium oxalate monohydrate that reacted with ferric chloride requires a chemical calculation involving stoichiometry, which falls within the realm of college-level chemistry. However, since the question does not provide the necessary stoichiometric information such as the balanced chemical equation involved in the reaction between potassium oxalate monohydrate and ferric chloride, a direct and accurate answer cannot be given. Therefore, it is paramount to have the balanced chemical equation before commencing any calculations to identify the molar ratio between the reactants and ultimately determine the mass of potassium oxalate monohydrate that reacted. Additional information about the product formation, concentration and volume of reactants in standard conditions will also be needed to solve the problem accurately.