In chemistry|lang=en terms the difference between electrophilic and hydrohalogenation

is that electrophilic is (chemistry) of, or relating to an electrophile; electron deficient while hydrohalogenation is (chemistry) the electrophilic addition of hydrohalic acids to alkenes to yield the corresponding haloalkanes.

As an adjective electrophilic

is (chemistry) of, or relating to an electrophile; electron deficient.

As a noun hydrohalogenation is

(chemistry) the electrophilic addition of hydrohalic acids to alkenes to yield the corresponding haloalkanes.