Step 1: Write down the equilibrium expression for K\(_p\).
The given reversible reaction in the gaseous phase is:
\[ \operatorname{N}_2\operatorname{O}_4(\operatorname{g}) \rightleftharpoons 2\operatorname{NO}_2(\operatorname{g}) \] For a general reversible reaction \(aA(g) + bB(g) \rightleftharpoons cC(g) + dD(g)\), the equilibrium constant in terms of partial pressures, K\(_p\), is given by: \[ K_p = \frac{(P_C)^c (P_D)^d}{(P_A)^a (P_B)^b} \] For the given reaction, the expression for K\(_p\) is: \[ K_p = \frac{(P_{\operatorname{NO}_2})^2}{P_{\operatorname{N}_2\operatorname{O}_4}} \] where \(P_{\operatorname{NO}_2}\) is the partial pressure of NO\(_2\) at equilibrium and \(P_{\operatorname{N}_2\operatorname{O}_4}\) is the partial pressure of N\(_2\)O\(_4\) at equilibrium.
Step 2: Identify the given values from the problem statement.
We are given:
Equilibrium constant, \(K_p = 0.113 \operatorname{atm}\)
Partial pressure of N\(_2\)O\(_4\) at equilibrium, \(P_{\operatorname{N}_2\operatorname{O}_4} = 0.2 \operatorname{atm}\) We need to find the partial pressure of NO\(_2\) at equilibrium, \(P_{\operatorname{NO}_2}\).
Step 3: Substitute the known values into the K\(_p\) expression and solve for the unknown partial pressure.
Substitute the given values into the \(K_p\) expression: \[ 0.113 = \frac{(P_{\operatorname{NO}_2})^2}{0.2} \] Now, rearrange the equation to solve for \((P_{\operatorname{NO}_2})^2\): \[ (P_{\operatorname{NO}_2})^2 = 0.113 \times 0.2 \] \[ (P_{\operatorname{NO}_2})^2 = 0.0226 \] To find \(P_{\operatorname{NO}_2}\), take the square root of both sides: \[ P_{\operatorname{NO}_2} = \sqrt{0.0226} \] \[ P_{\operatorname{NO}_2} \approx 0.15033 \]
Step 4: Round the answer and compare with the given options.
Rounding the calculated value to two or three significant figures, we get: \(P_{\operatorname{NO}_2} \approx 0.15 \operatorname{atm}\) This value matches option (4).
The final answer is $\boxed{0.15}$.
For the reaction: $A_2(g) \rightleftharpoons B_2(g)$
The equilibrium constant $K_c$ is given as 99.0. In a 1 L closed flask, two moles of $B_2(g)$ is heated to $T(K)$. What is the concentration of $B_2(g)$ (in mol L$^{-1}$) at equilibrium?
At 1000 K, the value of $K_c$ for the below reaction is $10 \text{ mol L}^{-1}$. Value of $K_p$ (in atm) is (given $R = 0.082 \text{ atm L mol}^{-1} \text{K}^{-1}$)
${\{A(g) <=> B(g) + C(g)}$