Maximum molarity of CuS in aqueous solution = Solubility of CuSin mol‌L–1
If S is the solubility of CuS in mol‌L–1 , then
‌CuS⇌Cu2++S2−, Ksp= [ Cu2+ ] [ S2−] =S×S=S2
∴‌‌S2=6×10−16 or S=√6×10−16 =2.45×10−8 ‌mol‌ ‌L−1