Question

Identify the reaction for which \( K_p = K_c \):

• A. \( A_2(g) + B_2(g) \rightleftharpoons A_2B_4(g) \)
• B. \( 2A_2(g) + B_2(g) \rightleftharpoons A_4B_2(g) \)
• C. \( A_2(g) + B_2(g) \rightleftharpoons 2AB(g) \)
• D. \( A_2(s) + B_2(g) \rightleftharpoons C_2(s) \)

Hint:

For equilibrium reactions, the relationship \( K_p = K_c \) holds true when the total number of moles of reactants and products is the same.

Answer 1

The Correct Option is C

Step 1: For the equilibrium reaction to have \( K_p = K_c \), the relationship between pressure and concentration should be the same. This happens only when the total number of moles of reactants and products on both sides of the equation are equal, i.e., no change in volume. 

Step 2: Consider the reaction: \[ A_2(g) + B_2(g) \rightleftharpoons 2AB(g) \] In this case, the number of moles of reactants is \( 1 + 1 = 2 \), and the number of moles of products is also 2. This results in the equality of \( K_p \) and \( K_c \), as the mole ratio of reactants and products is equal.

 Step 3: Thus, the correct reaction for which \( K_p = K_c \) is: \[ A_2(g) + B_2(g) \rightleftharpoons 2AB(g) \]