• # question_answer 52)   Boric acid is an acid because the molecule : (a) contains replaceable hydrogen ion                    (b) gives up a proton (c) accepts$O{{H}^{-}}$ from water releasing proton    (d) combines with proton from water molecule

(c) ${{H}_{3}}B{{O}_{3}}$or${{H}_{3}}B{{O}_{3}}$ in aqueous solution coordinates with a water molecule to form a hydrated species.   ${{B}^{3+}}$ion pulls the $\sigma$-electron charge of the coordinated O-atom towards itself. The coordinated oxygen, in turn, pulls the $\sigma$-electron charge of the O-H bond of the attached water molecule. This facilitates the removal of ${{H}^{+}}$ ion from the O-H bond. Thus, the aqueous  solution of${{H}_{3}}B{{O}_{3}}$ acts as a weak acid.     or$B{{(OH)}_{3}}$ accepts $O{{H}^{-}}$ from water and releases ${{H}^{+}}$ and it acts as a weak acid.