Question

The ratio of dissociated water to that of undissociated water

Answer 1

dissociated (ion-pair) structures of (H2O)n and NH3(H2O)n−1 (n = 5, 8, 9, 21) using density functional theory (DFT) and second order Moller−Plesset perturbation theory (MP2). The stability, thermodynamic properties, and infrared spectra were also studied. The dissociated (ion-pair) form of the clusters tends to favor the solvent-separated ion-pair of H3O+/NH4+ and OH−. As for the NH3(H2O)20 cluster, the undissociated structure has the internal conformation, in contrast to the surface conformation for the (H2O)21 cluster, whereas the dissociated structure of NH3(H2O)20 has the surface conformation. As the cluster size of (H2O)n/NH3(H2O)n−1 increases, the difference in standard free energy between undissociated and dissociated (ion-pair) clusters is asymptotically well corroborated with the energy change at infinite dilution of H3O+/NH4+ and OH−. The predicted NH and OH stretching frequencies of the undissociated and dissociated (ion-pair) clusters are discussed.

Answer 2

The ratio of dissociated water to that of undissociated water is $1.8* 10^{-9}$.

Given,

The density of pure water = 1000 g/L

Molar mass of water= 18 g/mol.

To Find,

The ratio of dissociated water to that of undissociated water.

Solution,

The density of pure water = 1000 g/L

Molar mass of water= 18 g/mol.

Let us find the Molarity of pure water= [H2O] = (1000 g/L)(1 mol/ 18g)

                                                                                                     = 55.55M

Therefore, the ratio of undissociated water (H+) to that of undissociated water =

$10^{-7} / (55.55) = 1.8 * 10^{-9}$.

Hence, the equilibrium is inclined towards the undissociated water.