Chapter 4, Problem 71QAP

Calcium in blood or urine can be determined by precipitation as calcium oxalate, CaC₂O₄. The precipitate is dissolved in strong acid and titrated with potassium permanganate. The equation for reaction is

${\text{2MnO}}_{\text{4}}{}^{-}\left(aq\right)+{\text{6H}}^{+}\left(aq\right)+{\text{5H}}_{\text{2}}{\text{C}}_{\text{2}}{\text{O}}_{\text{4}}\left(aq\right)\to {\text{2Mn}}^{\text{2}+}\left(aq\right)+\text{1}0{\text{CO}}_{\text{2}}\left(g\right)+{\text{8H}}_{\text{2}}\text{O}$

A 24-hour urine sample is collected from an adult patient, reduced to a small volume, and titrated with 26.2 mL of 0.0946 M KMnO₄. How many grams of calcium oxalate are in the sample? Normal range for Ca²⁺ output for an adult is 100 to 300 mg per 24 hour. Is the sample within the normal range?