<p>The ratio of amounts of&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>H</mi><mn>2</mn></msub><mi>S</mi></math>&nbsp;needed to precipitate all the metals ions from 100 mL of 1 M&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>A</mi><mi>g</mi><mi>N</mi><msub><mi>O</mi><mn>3</mn></msub></math>&nbsp;and 100 mL of 1 M&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>C</mi><mi>u</mi><mi>S</mi><msub><mi>O</mi><mn>4</mn></msub></math>&nbsp;is:</p>