sodium carbonate is added to a solutionnin which the concentration of Ni ion is .003M does NiCO3 precipitate?

Question

a) when the concentration of the carbonate is 1.0E-06M
b) or when its 100times greater (1.0E-04 M
the equilibrium process is NiCO3(s)= Ni (aq) +CO3(aq) ksp=6.6E-9

Answer 1

The product of solubility of NiCO3--->Ni+++CO3--
Ps=[Ni++][CO3--] and [Ni++]= [CO3--] =x

6.6 10^-9 =x^2 = 8.12*10^-5
a) 10^-6 is lower so no precipitation
b) 10^-4 is higher and so precipitation