JEE Main & Advanced Chemistry Equilibrium / साम्यावस्था Question Bank Self Evaluation Test - Equilibrium

  • question_answer
    \[{{K}_{c}}\] for \[PC{{l}_{5}}(g)\rightleftharpoons PC{{l}_{3}}(g)+C{{l}_{2}}(g)\] is 0.04 at \[250{}^\circ C\]. How many moles of \[PC{{l}_{5}}\] must be added to a 3 L flask to obtain a \[C{{l}_{2}}\] concentration of 0.15M

    A) 4.2 moles

    B) 2.1 moles

    C) 5.5 moles          

    D) 6.3 moles

    Correct Answer: B

    Solution :

    [b] At equilibrium the moles of \[C{{l}_{2}}\] must be \[=0.15\times 3=0.45\]  \[\begin{align}   & \begin{matrix}    {} & {} & {} & \,\,\,\,\,\,\,\,\,PC{{l}_{5}}\rightleftharpoons PC{{l}_{3}}+C{{l}_{2}}  \\ \end{matrix} \\  & \begin{matrix}    \text{Eqm}\text{.}\,\,\text{Conc}\text{.} & \frac{x-0.45}{3} & \frac{0.45}{3} & \frac{0.45}{3}  \\ \end{matrix} \\ \end{align}\] \[{{K}_{c}}=\frac{\left[ PC{{l}_{3}} \right]\left[ C{{l}_{2}} \right]}{\left[ PC{{l}_{5}} \right]}\] \[\therefore 0.04=\frac{0.15\times 0.15}{(x-0.45)/3}\] \[\therefore \text{ }x=2.1\text{ }moles\]


You need to login to perform this action.
You will be redirected in 3 sec spinner