An unknown sparingly soluble salt of formula is studied at three pH values

CHEMISTRY · Single correct · AP · Chemistry · Acids and Bases · Acids and Bases

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-}

(b)

\text{Cl}^-

(c)

\text{CO}_3^{2-}

(d)

\text{S}^{2-}