Among the following properties, how many increases down the group for halogens?
i) Chemical reactivity of halogens                             

ii) Reducing character of halogens
iii) Melting point of halogens                                     

iv) Covalent character of metal halides
v) Dissociation enthalpy of  $\mathrm{H}-\mathrm{X}$ bond                  

vi) $p{K}_a$ of aqueous HX
vii) Boiling points of  halogens