Figure 9: Absorption spectrum of reaction mixture with and without promoter (in absence of substrate): (i) (Cr(VI))T=5 × 10-4 mol dm-3, (H2SO4)T=0.5 mol dm-3 (ii) (Cr(VI))T=5×10-4 mol dm-3, (H2SO4)T=0.5 mol dm-3, (phen)T=25 × 10-4 mol dm-3 . Temp=30°C.