p-block

Chemically, it acts as a tribasic acid—an acid that can dissociate successively to produce three hydrogen ions in solution.

However, because it dissociates to such a small extent, it is a very weak acid

cud another reson be that it is also a Lewis acid and hence it is a weak acid?

due to backbonding from oxygen(pπ-pπ),electron deficiency on boric acid(lewis acid)is compensated
=>weak acid

HBO₃ is a weak acid because the electrons or the +I effect is given to and H⁺
ions are not easily given out
It can also be explained due to back bonding if O₂ which is pÎ -pÎ thus making it a weak acid