Question

Ka2 is very less than Ka1 for H2SO4 in water..y?

Answer 1

When H2SO4 forms HSO4⁻ and H⁺ ions than Ka1 exist. And when H2SO4 forms SO4²⁻ and H⁺ ion than Ka2 is formed. It is easier to release a H⁺ ion as compare to HSO4⁻ ion from a neutral H2SO4. Thus Ka2 is less seen than Ka1

Answer 2

Because when h2so4 dissociates into h+ and hso4- the single electron on the oxygen is deoocalised between  three oxygens while in so4-2 two electrons are deoocalised between 4 oxygens ,that is one electron is deoocalised between two oxygens which says that in so4-2 electron droocalisation is less so the hybrid is in more energetic state than hso4-.