a. Which isotpe of hydrogen is used as a tracer in organic reactions.?
b.Concentrated `H_(2)SO_(4)` cannot be used for drying `H_(2)`. Why?
c. The electrolysis of water of manufactures `H_(2)` gas is always carried out in presence of acid `(H_(2)SO_(4))` or alkali `(KOH)`, yet no `SO_(4)^(2-)` or `K^(o+)` are discharged. Why?

Explanation

(a) Hydrogen has three isotopes: protium or hydrogen , `._(1)^(1)H`, deuterium (`._(1)^(2)H` or `D`) and tritium (`._(2)^(3)(H)` or `T`). Due to the 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. 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.
(b) Conc `H_(2)SO_(4)` on absorbing water `(H_(2)O)` from moist `H_(2)` produces so much heat that `H_(2)` catches fire.
(c) Sulphate and potassium ions are not discharged as the discharge potential of `SO_(4)^(2-)` ion is much higher than `overset(Theta)(O)H` 1 ion and the discharge potential of `K^(ɵ)` ion is much higher than `H^(o+)` ion.