Question

Consider the following reaction where Kc = 10.5 at 350 K: 2 CH2Cl2 (g) CH4 (g) + CCl4 (g) A reaction mixture was found to contain 1.15×10-2 moles of CH2Cl2 (g), 5.11×10-2 moles of CH4 (g), and 3.61×10-2 moles of CCl4 (g), in a 1.00 liter container. Indicate True (T) or False (F) for each of the following: ___ 1. In order to reach equilibrium CH2Cl2(g) must be produced . ___ 2. In order to reach equilibrium Kc must increase . ___ 3. In order to reach equilibrium CH4 must be produced . ___ 4. Qc is less than Kc. ___ 5. The reaction is at equilibrium. No further reaction will occur.

Answer 1

Answer:

The given reaction is:  

2CH₂Cl₂ (g) ⇒ CH₄ (g) + CCl₄ (g), the reaction Q is,  

Q = [CH₄][CCl₄]/[CH₂Cl₂]²

Based on the given question, the values of Kc is 10.5 at 350 K, and the moles of CH₂Cl₂ is 1.15 × 10⁻² moles, moles of CCl₄ is 3.61 × 10⁻² moles, and the moles of CH₄ is 5.11 × 10⁻² moles. Now putting the values we get,  

Q = (5.11 × 10⁻²) (3.61 × 10⁻²) / (1.15 × 10⁻²)²

Q = 13.95

It is evident that the value of Q is more than Kc, thus, the reaction will shift in backward direction as the concentration of products is more than the reactants.  

1. The given statement is false, as the concentration of reactant is required to increase, and the concentration of product is required to get consumed to attain equilibrium.  

2. The given statement is false, Kc or equilibrium constant is a fixed quantity, while there can be a reduction or enhancement in the Q based upon the condition.  

3. In the statement, CH₄ must be consumed not produced, it is not spell correctly. Now the given statement will become true, as to attain equilibrium the reaction is required to shift in backward direction, which is only feasible when there is consumption of the concentration of products.  

4. The given statement is false, as based on the calculations, Q > Kc.  

5. The statement is false as Q is not equal to Kc, it is greater than Kc.