Lubricants used for watches usually consist of long chain hydrocarbons.Oxidation by air from solid polymers that eventually destroy the effectiveness of the lubricants.It is believed that one of the initial steps in the oxidation is removal of a hydrogen atom (hydrogen abstraction).By replacing the hydrogen atoms at reactive sites with deuterium atom,it is possible to substantially slow down the overall oxidation rate.Why? (Hint:Consider the kinetic isotope effect.)