<p>Versene, a chelating agent having chemical formula&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>C</mi><mn>2</mn></msub><msub><mi>H</mi><mn>4</mn></msub><msub><mi>N</mi><mn>2</mn></msub><msub><mrow><mo>(</mo><msub><mi>C</mi><mn>2</mn></msub><msub><mi>H</mi><mn>2</mn></msub><msub><mi>O</mi><mn>2</mn></msub><mi>N</mi><mi>a</mi><mo>)</mo></mrow><mn>4</mn></msub></math>. If each mole of this compound could bind 1 mole of&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>C</mi><msup><mi>a</mi><mrow><mn>2</mn><mo>+</mo></mrow></msup></math>, then the rating of pure versene expressed as mg of&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>C</mi><mi>a</mi><mi>C</mi><msub><mi>O</mi><mn>3</mn></msub></math>&nbsp;bound per g of chelating agent is:</p>