1. The problem statement, all variables and given/known data (c) (i) Neglecting hydrogen-bonding, calculate the interaction energy between (i) H3O+ and H2O and (ii) H3O+ and H3O+ , if each pair is separated by 0.3 nm and assuming that the aqueous solvent can be treated as a medium with constant relative permittivity. Using your result, comment on the likelihood of ideal behaviour by H3O+ at high molality. (ii) Using the Debye-Hückel Limiting Law, calculate the activity coefficient of H3O+ in a solution of 1 mol kg–1 HCl. What is the Debye length of the H3O+ ion in this solution and what does this tell us about the ideality of the solution? 2. Relevant equations Ion-dipole interaction: V=−qμ/(4πϵ0)r2 Dipole-dipole interaction: V=−2/3 μ12μ22/(4πϵ0)2r6 1/KBT Dipole moment: μ=qr Debye length: λD =√εTeff/n0e2 3. The attempt at a solution Are these the right equations to use? So for (i) I would use the first and for (ii) the second equation? What do I use to work out the dipole moment of H3O+? I'm assuming not the 0.3nm value and the charge is 1? For Debye length: ε = ε0(permittivity of a vacuum) x εr (relative permittivity). Would I assume room temperature so T = 298K ? I've got that n0 = constant volume density but not sure what that means, and e2 - are these both constants? Sorry for all the questions, really confused.