Our understanding of chemical reactivity is founded on the fundamental concepts of Electrophilicity and Neucleophilicity. There are a number of attempts of limited applicability in the literature to quantify these, but all depend on the reaction of molecular species where the unwanted steric effects complicate the measurements. Muonium with its minimum steric requirements are well suited to provide the kinetic measurements needed for such a quantificatioin. The unique RF-MuSR facility at ISIS provides a way of measuring such rates which are specific to each site of a molecule. The present application is to explore this possibility by using the compound benzoic acid where the hyperfine constants for addition to all the relevant sites are already available in the literature. We are after the absolute rate measurements using RF-MuSR.