Which isotope of hydrogen is used commoly as a tracer in organie reactions ?

Explanation

Hydrogen has three isotopes , viz, H, D and T . Due to difference in masses, the rate constants of these isotopes with the same substrate are different . In other words , both D and T show isotope effect. But since T is not only radioactive but is also least abundant hydrogen isotope, therefore, D is used as a tracer to study the mechanism of organic reactions.