Page 179 - Basic physical chemistry for the atmospheric sciences

Phosphorous H3P03 + H 20 µ H3Q + + H 2P03 K., = 3 . x 7 10 - 2
H2P03 + H2 0 µ H3Q + + H Po� - K. = 2 2 . 1 x 1 0 - 1
Sulfurous" H2S03 + H20 µ H30 + + HSQ3 - K., = 1 . 3 x 0 - 2
1
HS03 + H 20 µ H 30 + s o�- K8 = 2 6 .2 x 0 - s
1
+
Sulfu1icd H2S04 + H2 0 µ H 3Q + + H SQ4 - K., v ery large
=
HS04 + H 20 µ H 30 + + s o� - K82 = . 1 x 1 0 - 2
1
"H2C03 cannot b e isolated. I t is n equilibrium with H20 and dissolved C02• The value given fo r Ka, is actually
i
for the reaction
C02(aq + ) 2 H2 0 µ H 3Q + + H C03
Generally , aqueous solutions of C0 2 are treated as if the C0 2 (aq) were first converted to H2C03 , followed by
ionization of the H2C03.
4
bThe value for K 32 of H2S most commonly found in the older literature is about 1 x 10 - 1 , but current evidence
a-. suggests that the best value is considerably smaller.
Vi
cH2S03 is a hypothetical, nonisolatable species . The value listed for Ka, is actually for the reaction
S02(aq) + 2 H2 0 µ H 3Q + + HS03

dH2S04 is completely ionized in the first step .