i.) A temperature programmed desorption experiment in a H₂CO:H₂O ice mixture in a (a) 1:1, (b) 1:3, (c) 1:10 concentration ratio showing the desorption of surface H₂CO feature (M), along with the volcano desorption feature (V) and the co-desorption with H₂O feature (C) (from Noble et al. 2012). The M desorption feature of H₂CO is affected by the need for H₂CO to diffuse upward to the surface before desorbing. ii.) The isothermal kinetics of the HNCO + NH₃ → OCN⁻ + NH reaction is affected by the dilution of the reactants in the ASW ice in a HNCO:NH₃:H₂O ice mixture in (a) 1:50:100 and (b) 1:50:200 concentration ratio (Mispelaer et al. 2012).