Calculate the coupling constant between He and Hf. Explain how can this can help determine the stereochemistry (i. e. cis vs. trans) of the double bond. (7) Acetone is a symmetrical molecule, so there are two positions that can react. Draw the product you would expect to obtain if you used two molar equivalents of vanillin rather than one. c) Acetone is a symmetrical molecule, so there are two positions that can react. Draw the product you would expect to obtain if you used two molar equivalents of vanillin rather than one.