Question

PCl₅ decomposes into PCl₃ and Cl₂.It is found that if we put 3 moles of PCl₅ in a 2 litre flask at 600 k, 40% of it decomposes. Calculate equilibrium constant for the decomposition reaction.PCl₅ decomposes into PCl₃ and Cl₂.It is found that if we put 3 moles of PCl₅ in a 2 litre flask at 600 k, 40% of it decomposes. Calculate equilibrium constant for the decomposition reaction.

Answer 1

$$\begin{gathered} Thedecompositionreactionis \\ PC{l}_5\leftrightarrow PC{l}_3+C{l}_2 \\ Initial300 \\ Ateqm3-xxx(xistheamountreactedsox=40\%=0.4) \\ 3-0.40.40.4 \\ Eqmconc\frac{2.6}{2}\frac{0.4}{2}\frac{0.4}{2} \\ Eqmconcentrationis=\frac{numberofmoles}{volume} \\ {K}_c=\frac{\left[PC{l}_3\right]\left[C{l}_2\right]}{\left[PC{l}_5\right]}=\frac{{\displaystyle \frac{0.4}{2}}\times {\displaystyle \frac{0.4}{2}}}{{\displaystyle \frac{2.6}{2}}}=0.0308 \end{gathered}$$