question_answer 40)

    Affinity for hydrogen decreases in the group from fluorine to iodine. Which of the halogen acids should have highest bond dissociation enthalpy? (a) HF                                    (b) HCl          (c) HBr                                  (d) HI

Answer:

                    (a) HF    On moving top to bottom       HCl   · Size of halogen atom increases       HBr  · H-X bond length increases       HI     · Bond dissociation enthalpy    Decreases