Question:
Ka, 2Ka and 3Ka is the respective ionisation constants for the following
reactions.
H2S ⇌ H+ + HS–
HS– ⇌ H+ + S2–
H2S ⇌ 2H+ + S2–
The correct relationship between Ka1 , Ka2 and Ka3 is
(i) Ka3 = Ka1 × Ka2
(ii) Ka3 = Ka1 + Ka2
(iii) Ka3 = Ka1 – Ka2
(iv) Ka3 = Ka1 /Ka2
Solution:
Option (i) is the answer.