(N/A) Color: Pure alkyl halides are colorless,but bromides and iodides develop color when exposed to light.
$(b)$ Odor: Many volatile halogenated compounds possess a sweet smell.
$(c)$ Density: Bromo,iodo,and polychloro derivatives of hydrocarbons are heavier than water. The density increases with an increase in the number of carbon atoms,the number of halogen atoms,and the atomic mass of the halogen atoms.
Example: $(i)$ The densities of $n-C_3H_7Cl$,$n-C_3H_7Br$,and $n-C_3H_7I$ are $0.89$,$1.335$,and $1.747 \ g \ mL^{-1}$ respectively,showing an increase due to the increasing atomic mass of the halogens $(Cl, Br, I)$. $(ii)$ The densities of $CH_2Cl_2$,$CHCl_3$,and $CCl_4$ are $1.336$,$1.489$,and $1.595 \ g \ mL^{-1}$ respectively,showing an increase due to the increasing number of $-Cl$ atoms.