The following reaction has an equilibrium constant [tex]\( K = 1.0 \times 10^5 \)[/tex]. What is the concentration relationship between products and reactants at equilibrium?

[tex]\[ N_{2(g)} + 3H_{2(g)} \longleftrightarrow 2NH_{3(g)} \][/tex]

A. Reactants are favored
B. The reaction is incomplete and reaches equilibrium at a later stage
C. Concentrations of products and reactants are approximately equal
D. Products are favored



Answer :

To determine the relationship between the concentrations of the products and reactants at equilibrium for the reaction given:

[tex]$ N_2(g) + 3 H_2(g) \longleftrightarrow 2 NH_3(g) $[/tex]

we need to consider the value of the equilibrium constant [tex]\( K \)[/tex].

The equilibrium constant [tex]\( K \)[/tex] for a reaction is defined as:

[tex]\[ K = \frac{[\text{products}]}{[\text{reactants}]} \][/tex]

For the given reaction, the expression for the equilibrium constant [tex]\( K \)[/tex] is:

[tex]\[ K = \frac{[NH_3]^2}{[N_2][H_2]^3} \][/tex]

Given that [tex]\( K = 1.0 \times 10^5 \)[/tex], let’s analyze what this large value means.

### Analyzing the Value of [tex]\( K \)[/tex]

- Value of [tex]\( K \)[/tex]: The value [tex]\( 1.0 \times 10^5 \)[/tex] is very large (100,000).
- Implication: A large equilibrium constant means that the numerator (the concentration of products) is much greater than the denominator (the concentration of reactants). This implies that at equilibrium, there is a much higher concentration of products compared to reactants.

### Conclusion

Given the very large value of the equilibrium constant:

1. Reactants are favored: No. A large [tex]\( K \)[/tex] suggests products are favored.
2. The reaction is incomplete and reaches equilibrium at a later stage: No. A large [tex]\( K \)[/tex] indicates the reaction strongly favors the formation of products rather than being incomplete.
3. Concentrations of products and reactants are approximately equal: No. If [tex]\( K \)[/tex] were close to 1, then this could be true. However, [tex]\( 1.0 \times 10^5 \)[/tex] is far from 1.
4. Products are favored: Yes. As [tex]\( K = 1.0 \times 10^5 \)[/tex] is much greater than 1, this means the reaction heavily favors the products at equilibrium.

Therefore, the relationship between the concentrations at equilibrium is that products are favored.