The two half reaction, one separately are as follows S8+16e−⟶8S2− (Reduction)
S8+12H2O⟶4S2O32−+24H++16e−
2S8+12H2O⟶8S2−+4S2O32−+24H+
For balancing in basic medium, Add an equal number of OH−that of H+, we get 2S8+12H2O+24OH−⟶8S2−+4S2O32−+24H2O 2S8+24OH−⟶8S2−+4S2O32−+12H2O or S8+12OH−⟶4S2−+2S2O32−+6H2O . . . (i) On comparing (i) with S8+aOH−(aq)⟶bS2−(aq)+cS2O32−+dH2O We get, a=12 b=4;c=2;d=6