Ortho-hydrogen and Para-hydrogen resemble in which one of the following properties?
Ortho-hydrogen and Para-hydrogen resemble in which one of the following properties?
The correct option is D Chemical properties
Chemical properties of both the isomeric forms - para-hydrogen and ortho-hydrogen are similar.
In the para isomer (of hydrogen molecule - H2) the protons of the two atoms, which are held together by a covalent bond have opposite spins. This isomer exists at a lower energy state than the 'excited' ortho isomer, which has the mentioned protons in parallel or similar spins. At room temperature and thermal equilibrium, H2 molecules are comprised of 75 % orthohydrogen and 25 % parahydrogen. Do remember that the isomer with opposite spins - parahydrogen is the more stable one. As we approach absolute zero, at equilibrium, the composition is significantly skewed in favour of the more stable isomer - para.
Clearly a) Nuclear spins are not similar. They are opposite
At thermal equilibrium at room temperature, Ortho:para = 3:1. This composition is very sensitive to temperature. So clearly the options b and c are not appropriate. The isomers differ in heat capacities, entropy and thermal conductivities.
Chemical properties
Chemical properties of both the isomeric forms - para-hydrogen and ortho-hydrogen are similar.
In the para isomer (of hydrogen molecule - H2) the protons of the two atoms, which are held together by a covalent bond have opposite spins. This isomer exists at a lower energy state than the 'excited' ortho isomer, which has the mentioned protons in parallel or similar spins. At room temperature and thermal equilibrium, H2 molecules are comprised of 75 % orthohydrogen and 25 % parahydrogen. Do remember that the isomer with opposite spins - parahydrogen is the more stable one. As we approach absolute zero, at equilibrium, the composition is significantly skewed in favour of the more stable isomer - para.
Clearly a) Nuclear spins are not similar. They are opposite
At thermal equilibrium at room temperature, Ortho:para = 3:1. This composition is very sensitive to temperature. So clearly the options b and c are not appropriate. The isomers differ in heat capacities, entropy and thermal conductivities.
