For the formation of hydrogen iodide, H2(g) + 12(g) - 2HI(g) the value of the equilibrium constant at 700K is 54.7. If one mole of H2 and one mole of 12 are the
only materials initially present, what will be the equilibrium concentrations of H2,
12, and HI.

t 700 K, the equilibrium constant for the reaction;

H  

2(g)

​  

+I  

2(g)

​  

⇌2HI  

(g)

​  

 is 54.8.

If 0.5 mol litre  

−1

 of HI  

(g)

​  

 is present at equilibrium at 700 K, what are the concentrations of H  

2(g)

​  

 and I  

2(g)

​  

 assuming that we initially started with HI  

(g)

​  

 and allowed it to reach equilibrium at 700 K.

the electronic configuration of an atom with eight electrons is 1s²2s²2p⁴. the orbital diagrams are shown in the figure.

as per the hunds rule:

1. electrons tend to avoid being in the same orbital as per as practicable.

2. electrons in different orbitals of the same energy will have their spin parallel.

this can be illustrated from the multiplicity of the orbitals of the atom. as there are four electrons in the p orbital and p orbital has 3 sub-shells. the electrons can be fed in different ways as shown in the figure but the correct orbital diagram will be as per the hunds rule.