CHAP. 11: ELECTROCHEMISTRY [CONTENTS] 395
Solution
From the material balance it follows thatcAg+ = 2c andcCrO 24 − = c+ 0. 01 , wherec is
the concentration of the dissolved chromate. We substitute into (11.107) while assuming that
γ±= 1.
9 × 10 −^12 = (2c)^2 ×(c+ 0.01)= 4. ×c^2 × 0 .01 =⇒ c= 1. 5 × 10 −^5 mol dm−^3.
This result can be made more accurate by considering the mean activity coefficient. As compared
with the solubility in pure water, see the preceding Example, the solubility of silver chromate
decreased almost 10-times.
