Question

In the following reaction $P_{4}(g)+6Cl_{2}(g) \rightleftharpoons 4PCl_{3}(g)$, equilibrium is established by adding equal moles of $P_{4}(g)$ and $Cl_{2}(g)$. Therefore, at equilibrium:

• A. $[Cl_{2}] > [PCl_{3}]$
• B. $[Cl_{2}] < [P_{4}]$
• C. $[PCl_{3}] > [P_{4}]$
• D. $[P_{4}] = [PCl_{3}]$

Hint:

The reactant with the higher stoichiometric coefficient is consumed faster.

Answer 1

The Correct Option is B

Step 1: Concept
Stoichiometry dictates the rate at which reactants are consumed.

Step 2: Meaning
The reaction requires 6 moles of $Cl_2$ for every 1 mole of $P_4$.

Step 3: Analysis
If you start with equal moles, $Cl_2$ is consumed 6 times faster than $P_4$. As the reaction proceeds toward equilibrium, a much larger amount of $Cl_2$ will be used up compared to $P_4$.

Step 4: Conclusion
Consequently, the remaining concentration of $Cl_2$ at equilibrium will be less than the concentration of $P_4$. Final Answer: (B)