The following cell was constructed to find the difference in Ksp between two nat

Question

The following cell was constructed to find the difference in Ksp between two naturally occurring forms of CaCO3(s), called calcite and aragonite.
Pb(s) | PbCO3(s) | CaCO3 (s, calcite) | buffer (pH 7.00) || buffer (pH 7.00) | CaCO3 (s, aragonite) | PbCO3(s) | Pb(s)
Each compartment of the cell contains a mixture of solid PbCO3 (Ksp = 7.4 x 10-14) and either calcite or aragonite, both of which have Ksp ~ 5 x 10-9. Each solution was buffered
to pH 7.00 with an inert buffer, and the cell was completely isolated from atmospheric CO2. The measured cell voltage was -1.8 mV. Find the ratio of solubility products, Ksp
(for calcite) / Ksp (for aragonite).

Explanation / Answer

Nernst equation gives

E= Eo-0.0592/n log calcite/aragonite

Eo = 0 as it is a concentration cell

-1.8 x 10-3 = -0.0592/2 log calcite/aragonite

log calcite/aragonite = 0.0608

calcite/aragonite = 100.0608

calcite/aragonite = 1.15

This is the ratio of their Ksp's

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.