Question

Tritium undergoes radioactive decay giving
A. $\alpha $-particles
B. $\beta $ -particles
C. Neutrons
D. $\gamma $-rays

Answer 1

Hint: Tritium is an isotope of elemental hydrogen. Out of three isotopes of elemental hydrogen, tritium is radioactive. These isotopes have very low natural abundance. Due to its radioactive nature, it undergoes radioactive decay and emits radiation to transform into a stable nucleus.

Complete Step by Step Answer:
In the periodic table, elemental hydrogen has three different isotopes with different neutron numbers. They are protium ($^{1}H$), deuterium ($^{2}H$), and tritium ($^{3}H$). Protium and deuterium have no radioactive properties except the isotope tritium.

Tritium undergoes radioactive decay and emits radiation of a very weak beta particle ($\beta $) and transforms into a stable nucleus of helium.
$^{3}H\to _{2}^{3}He+_{-1}^{0}\beta $
Therefore tritium undergoes radioactive decay giving $\beta $-particles.
Thus, option (B) is correct.

Additional information: Tritium can be artificially produced by the nuclear fission reaction. From nuclear weapon tests, a tremendous amount of tritium originated for example during the test of the hydrogen bomb. It is naturally formed in the upper atmosphere when cosmic rays strike air molecules. The half-life of tritium is $12.3$ years and the radioactivity of tritium per $1$kg in weight is $3.6\times {{10}^{14}}$Bq. During radioactive disintegration, tritium emits beta particles with a maximum energy of $18.6$ keV.

Note: Tritium has a very harmful effect on the human body. It enters the human body by swallowing tritiated water. People can inhale tritium as a gas in the air and absorb it through their skin. It is found under investigation that bound tritium remains in the human body for a long time and continuous radiation increases the risk of developing cancer.