Question

Dihydrogen reacts with dioxygen ${O_2}$ to form water. Write the name and formula of the product when the isotope of hydrogen which has one proton and one neutron in its nucleus is treated with oxygen. Will the reactivity of both the isotopes be the same towards oxygen? Justify your answer.

Answer 1

Hint: Isotopes are the different species of atom of the chemical element which shows similarity in the atomic number and their position but differs in their atomic masses. Isotopes have the same chemical nature as the chemical element. Hydrogen atoms have three isotopes, protium with atomic mass 1, deuterium with atomic mass 2 and tritium with atomic mass 3.

Complete step by step answer:
The reaction of dihydrogen with dioxygen to form water is shown below.
$2{H_2} + {O_2} \to 2{H_2}O$
There are a total three types of isotopes of hydrogen.
(i) Protium
(ii) Deuterium
(iii) tritium
Protium is composed of one proton and one electron. It does not have any neutrons.
Deuterium is composed of one proton and one neutron.
Tritium is composed of one proton and two neutrons.
Thus, the only isotope of hydrogen which has one proton and one neutron is deuterium.
The reaction of deuterium and oxygen is shown below.
$2{D_2} + {O_2} \to {D_2}O$
Deuterium one reacting with oxygen forms deuterium oxide.
The formula of deuterium oxide is ${D_2}O$.
Deuterium oxide is a stable product as compared to ${H_2}O$, therefore it will not undergo dissociation easily like ${H_2}O$.
The reactivity of the compound is dependent on the bond length, longer the bond length between the atoms, more reactive will be the compound.
${H_2}O$ has greater bond length as compared to ${D_2}O$, therefore it will react easily and the ${H^ + }$ released will be more acidic than the ${D^ + }$.

Note: In ${D_2}O$ the removal of ions needs much high bond dissociation energy, therefore it generally forms free radical not ions in standard condition. ${D_2}O$ is also known as heavy water.