I. II. III. The compounds are treated separately with acidified potassium dichromate(VI) solution. Which will produce a colour change from orange to green? Which compound reacts most rapidly by a SN1 mechanism? Which compound shows three different environments for hydrogen atoms in the 1H NMR spectrum? Which statement is correct regarding the structure of benzene? A. B. C. D. The 1H NMR spectrum of benzene shows six different environments for H atoms.