Why is for H2SO4in water?


H2SO4 is dibasic acid (two replacable H+ ions) . In aqueous solution it dissociates in two steps as follows:


H2SO4 + H2O H3O+ + HSO4



(Ka1 = very large)



HSO4 + H2O H3O+ + SO42



(Ka2 = 1.2 x 10–2)




The formula for dissociation constants are:




The neutral H2SO4 molecule has more tendency to lose a proton (H+) than the Lowry-Bronsted base (which can donate electron i.e. accept a proton H+) HSO4-. This is because a neutral has a much higher tendency to lose a proton than the negatively charged. Thus, the former is a much stronger acid than the latter.


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