question_answer 50)

      Elements of group- 15 form compounds in +5 oxidation state. However, bismuth forms only one well characterised compound in +5 oxidation state. The compound is (a)                              (b) (c)                            (d)

Answer:

                                  (b) Stability of + .5 oxidation state decreases top to bottom and + 3 oxidation state increases top to bottom due to inert pair effect. Meanwhile compound having + 5 oxidation state of Bi is. It is due to smaller size and high electronegativity of fluorine.