Q. The equilibrium, $P_{4}(s) + 6Cl_{2}(g) \rightleftharpoons 4PCl_{3}(g)$ attained by mixing equal moles of $P_{4}\ and\ Cl_{2}$ in a evacuated vessel. Then, at equilibrium,
A) $\left\lbrack Cl_{2} \right\rbrack > \left\lbrack PCl_{3} \right\rbrack$
B) $\left\lbrack Cl_{2} \right\rbrack > \lbrack P_{4}\rbrack$
C) $\left\lbrack P_{4} \right\rbrack > \lbrack Cl_{2}\rbrack$
D) $\left\lbrack PCl_{3} \right\rbrack > \lbrack P_{4}\rbrack$
Explanation
(c)
For the reaction,
$P_{4}(s) + 6Cl_{2}(g) \rightleftharpoons 4PCl_{3}(g)$
At t=0 1 1 0
At eq. $(1 - x)$ $(1 - 6x)$ $4x$
As $(1 - x) > (1 - 6x)$
Hence, at equilibrium $\left\lbrack P_{4} \right\rbrack > \lbrack Cl_{2}\rbrack$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.