The equilibrium constant of dissociation reaction of oxygen

\(\rm O_2 \rightleftharpoons 2O\)

at temperature 1000 K is obtained to be

Concept:
Equilibrium Constant

For the dissociation reaction of oxygen:

\(\text{O}_2 \leftrightarrow 2\text{O}\)

The equilibrium constant K is defined as:

\(K = \frac{[\text{O}]^2}{[\text{O}_2]}\)

At high temperatures, the dissociation of O2  to oxygen atoms is more significant. However, at 1000 K, the equilibrium concentration of atomic oxygen (O) is generally quite low, indicating a small value for K .

Analysis of Given Options

1. 3.3 × 10-20
   • This is a very low value, indicating very little dissociation of {O}_2 to {O} .
2. 2.5 × 10-10
   • A small value representing minimal dissociation, but larger than option 1.
3. 5.2 × 10-7
   • This value is higher and might be reasonable for some equilibrium reactions, but not typical for the dissociation of {O}_2 at 1000 K.
4. 1.4 × 10-37
   • Extremely low, suggesting virtually no dissociation, which is unrealistic for a measurable equilibrium constant at 1000 K.

At 1000 K, oxygen molecules ( O2 ) do not dissociate significantly into oxygen atoms ( {O} ) due to the strong O=O double bond. The equilibrium constant for such a reaction is usually very small, but still within a measurable range.

Conclusion

The most reasonable equilibrium constant for the dissociation reaction of oxygen at 1000 K would be 2.5 × 10^-10