The system CO2(g) + H2(g)<->H2O(g) + CO(g) is at equilibrium at some temperature. At equilibrium a 4.00 L vessel contains 1.00 mole CO2, 1.00 mole H2, 2.40 moles H2O, and 2.40

moles CO. How many moles of CO2 must be
added to the system to bring the equilibrium CO concentration to 0.679 mol/L?
Answer in units of moles

2 answers

........CO2 + H2 ==> H2O + CO
I......0.25..0.25....0.60..0.60
C........x....x......-x.....-x
E.....0.679+x etc.

Then solve for x = (CO2) in M, and M x L = mols.
The Ksp of Ni(CN)2 is 3.0 × 10−23. What is
the molar solubility of Ni(CN)2 in a 0.065 M KCN solution?
Answer in units of mol/L.

I found that the normal molar solubility is 1.957x10^-8, but I don't know how the KCN solution affects it.
Sig figs aren't accounted for.