The balanced ionic Equation in basic medium is : H2O + 2 CrO 42 -- + 3 HSnO2- ----> 2 CrO2- + 2 OH- + 3 HSnO3- The sum of the coefficients is = 1+2 + 3 + 2 + 2 + 3 = 13 Solution The balanced ionic Equation in basic medium is : H2O + 2 CrO 42 -- + 3 HSnO2- ----> 2 CrO2- + 2 OH- + 3 HSnO3- The sum of the coefficients is = 1+2 + 3 + 2 + 2 + 3 = 13.