Paramagnetism arises due to the presence of unpaired electrons in a molecule. Let’s analyze each molecule's electronic configuration to determine the number of paramagnetic molecules:
- O\(_2\) (Oxygen): Oxygen molecule has a total of 16 electrons. According to molecular orbital theory, the electronic configuration for O\(_2\) is: \[ (\sigma_{1s})^2 (\sigma_{1s}^*)^2 (\sigma_{2s})^2 (\sigma_{2s}^*)^2 (\sigma_{2p_z})^2 (\pi_{2p_x})^1 (\pi_{2p_y})^1 (\pi_{2p_x}^*)^0 (\pi_{2p_y}^*)^0 \] This shows that there are 2 unpaired electrons, making O\(_2\) paramagnetic.
- N\(_2\) (Nitrogen): Nitrogen molecule has a total of 14 electrons. Its molecular orbital configuration is: \[ (\sigma_{1s})^2 (\sigma_{1s}^*)^2 (\sigma_{2s})^2 (\sigma_{2s}^*)^2 (\sigma_{2p_z})^2 (\pi_{2p_x})^2 (\pi_{2p_y})^2 \] All electrons are paired in N\(_2\), so it is diamagnetic.
- F\(_2\) (Fluorine): Fluorine molecule has a total of 18 electrons. The electronic configuration is: \[ (\sigma_{1s})^2 (\sigma_{1s}^*)^2 (\sigma_{2s})^2 (\sigma_{2s}^*)^2 (\sigma_{2p_z})^2 (\pi_{2p_x})^2 (\pi_{2p_y})^2 (\pi_{2p_x}^*)^1 (\pi_{2p_y}^*)^1 \] This configuration shows 2 unpaired electrons, making F\(_2\) paramagnetic.
- B\(_2\) (Boron): Boron molecule has a total of 10 electrons. Its electronic configuration is: \[ (\sigma_{1s})^2 (\sigma_{1s}^*)^2 (\sigma_{2s})^2 (\sigma_{2s}^*)^2 (\pi_{2p_x})^1 (\pi_{2p_y})^1 \] This configuration shows 2 unpaired electrons, making B\(_2\) paramagnetic.
- Cl\(_2\) (Chlorine): Chlorine molecule has a total of 18 electrons. The electronic configuration is: \[ (\sigma_{1s})^2 (\sigma_{1s}^*)^2 (\sigma_{2s})^2 (\sigma_{2s}^*)^2 (\sigma_{2p_z})^2 (\pi_{2p_x})^2 (\pi_{2p_y})^2 (\pi_{2p_x}^*)^1 (\pi_{2p_y}^*)^1 \] This configuration shows 2 unpaired electrons, making Cl\(_2\) paramagnetic. Thus, the paramagnetic molecules are O\(_2\), F\(_2\), and B\(_2\). Therefore, the number of paramagnetic molecules is 3.
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
The total number of molecular orbitals formed from 2s and 2p atomic orbitals of a diatomic molecule is _________.
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)