Difference in electronic spin in ortho and para hydrogen
Answers
Ordinary dihydrogen is an equilibrium mixture of ortho and para hydrogen.
The amount of ortho and para hydrogen varies with temperature as:
At 0°K, hydrogen contains mainly para hydrogen which is more stable.
At the temperature of liquefaction of air, the ratio of ortho and para hydrogen is 1 : 1.
At the room temperature, the ratio of ortho to para hydrogen is 3 : 1.
Even at very high temperatures, the ratio of ortho to para hydrogen can never be more than 3 : 1.
Thus, it has been possible to get pure para hydrogen by cooling ordinary hydrogen gas to a very low temperature (close to 20 K) but it is never possible to get a sample of hydrogen containing more than 75% of ortho hydrogen
Hydrogen atoms consist of a proton and an electron. The proton has a charge of +1 and a spin. The spin can either be clockwise or counter-clockwise. So when you have a hydrogen molecule you have two possibilities: the two spins can both be aligned (both clockwise or both counter-clockwise) or they can be opposed
Ortho hydrogen:—
The hydrogen molecule in which both the protons in the nuclei of both hydrogen atoms spin in the same direction is called as ortho hydrogen. In this form the resultant nuclear spin is one.
Para hydrogen:—-
Hydrogen molecule in which both the protons in the nuclei of both hydrogen atoms spin in opposite direction is called para hydrogen. In this form resultant nuclear spin is zero.
