Question

In the given reaction : $A + 2B \rightleftharpoons 2C$ moles each of A and B present in 10 L of solution combine to form 1 mole of C. Calculate $K_c$ for the reaction.

• A. 1.5
• B. 6.67
• C. 0.15
• D. 2.3

Answer 1

Answer: (B)

6.67

Answer 2

$\begin{matrix}&A&+&2B&?&2C\\\ Initially mole&2&&2&&0\\\ At equilibrium&2-x&&2-2x&&2x\\\ &=1.5&&=1&&=1\end{matrix}$ As 1 mole of C is formed at equilibrium, $\quad\quad$2x = 1 $?$ x = 0.5 $? \quad$Equilibrium concentration of A = 1.5/10 $\quad\quad$B = 1/10 and C = 1/10 $K_{c}=\frac{\left[C\right]^{2}}{\left[A\right]\left[B\right]^{2}}=\frac{\left[1/10\right]^{2}}{\left[1.5 / 10\right]\left[1 / 10\right]^{2}}=6.67$