Note 501 — Chapter XIII · THE ARSENIC GROUP. SULPHO-ACIDS AND SULPHO-SALTS
Reading edition
On p. 238 the analogous equation for the condition of equilibrium of the anion of an oxygen acid with its components was developed. Applying the result to the ion SnO32− of stannic acid, H2SnO3, we have:
[Sn4+] × [O2−]3 / [SnO32−] = K.
It is evident, from the form of the equation, that for the stronger oxygen acids, which are most stable as acids and ionize as bases at most in traces, the value of the constant must be extremely small.