If silver hydroxide have acid properties, the addition of an alkali must suppress the hydrogen-ion and the hydroxide will go into solution as an argentate, MeAgO. We find, however, that sodium or potassium hydroxide, which would form an argentate very much more readily than ammonium hydroxide, has no solvent action on silver hydroxide (‹exp.›); on the contrary, quantitative experiments show that the alkali makes the hydroxide still less soluble than in pure water—as demanded by the solubility-product for the basic ionization. It is thus evident, that the solvent action of ammonium hydroxide is not due to its basic functions. We would suspect that we have here an action, in which ‹ammonia› is the active component, the product of a form of dissociation of ammonium hydroxide, of which the fixed alkalies are incapable. «The Complex Silver-Ammonium[425]-Ion.»—For a solution of ammonia, in water, we have the reversible reactions: [p218] HO^{−} + H^{+} + NH_{3} ⇄ NH_{4}^{+} + HO^{−} ⇄ NH_{4}OH, and we note that a molecule of ammonia appears to combine first with a hydrogen ion, to form an ammonium ion, and this then forms ammonium hydroxide with the hydroxide ion. This suggests that ammonia may have the capacity to combine with positive ions other than hydrogen ion, and with metal hydroxides other than water. For an analogous reaction of ammonia with silver ion and with silver hydroxide, we would have: NH_{3} + Ag^{+} + HO^{−} ⇄ (NH_{3}Ag)^{+} + HO^{−} ⇄ (NH_{3}Ag)OH. For the condition of equilibrium between ammonia, the silver-ion and the silver-ammonium-ion, we would have[426]: [NH_{3}] × [Ag^{+}] / [NH_{3}Ag^{+}] = K. Experimental investigations of the quantitative relations, obtaining in ammoniacal solutions containing silver compounds, show that ‹no constant› value is obtained for the ratio, as just developed. But the experimental data show equally conclusively,[427] that a constant is obtained, ‹when the concentration of the ammonia is raised to the second power, in the mathematical statement›. The significance of this change in the mathematical relation, it will be recalled (p. 94), is that two molecules of ammonia must combine with one silver ion to form an ion [(NH_{3})_{2}Ag]^{+}, whereas in the formation of the ammonium ion, NH_{4}^{+}, we have a single molecule of ammonia combining with one hydrogen ion. We have then 2 NH_{3} + Ag^{+} + HO^{−} ⇄ [(NH_{3})_{2}Ag]^{+} + HO^{−} ⇄ [(NH_{3})_{2}Ag]OH.