A chemist needs to dissolve at least of CoCO (s) per liter of solution at 25 °C

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

Problem

A chemist needs to dissolve at least

1.0\times10^{-3}\,\text{mol}

of CoCO

_3

(s) per liter of solution at 25 °C. The solubility product is

K_{sp}(\text{CoCO}_3)=1.4\times10^{-13}

and the second acid-dissociation constant of carbonic acid is

K_{a2}=4.8\times10^{-11}

. Assuming no other significant carbonate sources, what minimum pH will achieve the required solubility? (a)

2.70

(b)

6.50

(c)

3.46

(d)

3.00