The correct option is A (i) 1 or 2
(ii) 1
In case of acid-base reaction, the valency factor is the actual number of H+ or OH− replaced in the reaction. The acid or base may contain more number of replaceable H+ or OH− than actually replaced in reaction.
valency factor for acid is the number of H+ ion replaced by per molecule of the acid.
H3PO3 has 2 replacable H+ hence it's valency can be 1 or 2.
and H3BO3 has 3 hydrogen linked to oxygen yet all are not replacable
H3BO3+H2O→[B(OH)4]−+H3O+ thus mole of boric acid can give only one H+ ion hence valency factor is 1.