Structure and Bonding Effects on Acid Strength
When E is not constant, Ka varies with electronegativity of E.
H3BO3 H2CO3 HNO3
6 x 10-10 4 x 10-7 large
H3PO4
8 x 10-3
H3AsO4
6 x 10-3
In E-O-H, larger electronegativity of E makes the O-H bond easier to ionize by attracting electrons towards E
electronegativity increases