The maximum ease of abstraction of a hydrogen atom by a chlorine atom is shown by

all compounds are hydrocarbons so the reaction  for abstraction of chlorine is called chlorination and here chlorine is present in radical form and the reactivity depends on stability of hydrocarbon (or) radical produced from hydrocarbon. The stability of  hydrocarbons isBenzyl > allyl > 3o > 2o > 1o > −CH3​ > Vinyl > phenyl.