Chemistry

Problem

An unknown sparingly soluble salt

X

of formula

\text{M}_2\text{A}

is studied at three pH values. The mass of

X

that dissolves in 100\,mL of water at 25 °C is recorded in the table. pH Dissolved mass of

X

2.0 0.20 g 7.0 0.05 g 12.0 0.01 g Based on the trend in solubility, which anion is most likely

\text{A}^{2-}

in the salt? a)

\text{SO}_4^{2-}

\text{Cl}^-

\text{CO}_3^{2-}

\text{S}^{2-}