Thin layer chromatography (TLC) is used all the time to monitor reactions. Below is a typical TLC plate when viewed under UV light, showing a reaction that is almost complete. Note that when we monitor a reaction, we always include a 'mixed spot' (mix) that has both the starting material (SM) and the reaction products (react) in it. Sometimes the starting material and product can have very similar Rf values, so a mixed spot can help us 'spot' this. For the TLC plate below, fill in the Rf values (to two decimal places) for the starting material (SM) and the product (new spot seen in the 'react' spot). 10 9 8 7 9 5 4 3 2 1 0 S.M. Starting material (SM) Rf Reaction product (react) Rf mix react