The missing ion in the following equation Cr(OH)3+CIO−+OH−→?+Cl−+H2O  is

In basic medium, chromium salts from chromates. Therefore, the balanced equation is Cr(OH)3+2ClO+OH−→                                       CrO42−+2Cl−+2H2O Thus, the missing ion is CrO42−  and hence option (c) is correct.