Solid BaNO32 is gradually dissolved in a 1.0 × 10-4 M Na2CO3 solution. At what concentration of Ba2+, will a precipitate begin to form ?
KSP for BaCO3 = 5.1 × 10-9
4.1 × 10-5 M
5.1 × 10-5 M
8.1 × 10-8 M
8.1 × 10-7 M
Na2CO3 ⇌ 2Na+ + CO32-
Na2CO3 = CO32- = 1 × 10-4 M
BaCO3 ⇌ Ba2+ + CO32-
KSP BaCO3 = Ba2+ CO32-
Ba2+ = KSP BaCO3CO32-
Ba2+ = 5.1 × 10-91 ×10-4
Ba2+ = 5.1 × 10-5 M
Hence, at 5.1 × 10-5 concentration of Ba2+, a precipitate will begin to form.