For a reaction N2+O2=2NO
If Kc=10-30 at 25°C
One Can predict with solid reason?
(1) More NO is formed
(2) The forward reaction goes to completion
(3) The backward reaction goes to completion
(4) More reactant can consumed
Awkward question. Awkward answers. The best answer in the list is 3.
To predict the direction in which a reaction will proceed based on the value of the equilibrium constant (Kc), you need to compare the value of Kc to its magnitude.
In the given reaction N2 + O2 ↔ 2NO, if Kc = 10^-30 at 25°C, the magnitude of Kc is extremely small. Based on this information, we can make the following predictions:
(1) More NO is formed: Since the magnitude of Kc is very small, it indicates that the concentration of the products (NO) is significantly lower compared to the reactants (N2 and O2). Therefore, it is unlikely that more NO will be formed in this case.
(2) The forward reaction goes to completion: With a very small Kc value, it suggests that the forward reaction (N2 + O2 → 2NO) is not favored. Therefore, it is unlikely that the forward reaction will go to completion.
(3) The backward reaction goes to completion: Based on the value of Kc, it indicates that the concentration of the reactants (N2 and O2) is much higher compared to the products (NO). This implies that the backward reaction (2NO → N2 + O2) is favored and may go to completion.
(4) More reactant can be consumed: Since the backward reaction is favored (as indicated by the small Kc value), it suggests that more of the reactants (N2 and O2) can be consumed to form more products (NO). Therefore, it is likely that more N2 and O2 can be consumed in this case.
In summary, based on the given Kc value of 10^-30 at 25°C, the predictions with solid reasoning would be:
(3) The backward reaction goes to completion, and
(4) More reactants can be consumed.