The Ksp for Ag2C2O4 is calculated as follows
write the equation for dissociation for Ag2C2O4
that is Ag2C2O4 -----> 2Ag^+ + C2O4 -
the concentration of C2O4 ^2- = 2.2 x10^-4 and that of Ag = 2 x(2.2 x10^-4)
Ksp =( Ag+)^2 (C2O4-)
that is ( 2x2.2 x10^-4) ( 2.2 x10 ^-4) = 4.26 x10^-11