The following pictures represent solutions of CuS,which may also contain ions other than Cu 2+ and S 2- which are not shown.Gray spheres represent Cu 2+ ions and dotted spheres represent S 2- ions.
-If solution (1)is a saturated solution of CuS,which of solutions (2)-(4)are unsaturated?
A)only (2)
B)only (3)
C)only (4)
D)(3)and (4)

Question

The following pictures represent solutions of CuS,which may also contain ions other than Cu 2+ and S 2- which are not shown.Gray spheres represent Cu 2+ ions and dotted spheres represent S 2- ions. 
-If solution (1)is a saturated solution of CuS,which of solutions (2)-(4)are unsaturated?
A)only (2) 
B)only (3) 
C)only (4) 
D)(3)and (4)

Quizplus · Accepted Answer

In a saturated solution, the maximum amount of solute has been dissolved at a given temperature. If solution (1) is saturated with CuS, any solution with a lower concentration of CuS (less solute in the same amount of solvent) would be considered unsaturated. Solutions (3) and (4), having lower concentrations of CuS than the saturated solution (1), are therefore unsaturated.

The Following Pictures Represent Solutions of CuS,which May Also Contain