Question

How much PCl5 must be taken in a 9.2 L vessel to get 0.5 mole of Cl2 at a particular temp. The value of kc is 0.414

Answer 1

Answer:

0.56 moles of PCl₅ must be taken in a 9.2L vessel to get 0.5mol of Cl₂ at a particular temperature with an equilibrium constant of 0.414

Explanation:

Given that,

volume of PCl₅ = 9.2L

moles of Cl₂ = 0.5 mol.

Equilibrium constant, $K_{c}$ = 0.414mol/L

the chemical reaction is given by,

                               PCl₅ (g)     →     PCl₃ (g)  + Cl₂ (g)

at t=0, moles     :         x                    0             0

at equilibrium     :    x-0.5                  0.5          0.5

Concentration = no: of moles  / liters of solution

therefore the concentration of reactant and products :

       $[PCl_5]=\frac{x-0.5}{9.2}M$

        $[PCl_3]=\frac{0.5}{9.2}M$

          $[Cl_2]=\frac{0.5}{9.2}M$

the equilibrium constant $K_{c}$ is given by

            $K_c=\frac{[PCl_3][Cl_2]}{[PCl_5]}$

⇒      $0.414 =\frac{\frac{0.5}{9.2}\times \frac{0.5}{9.2} }{\frac{x-0.5}{9.2} }=\frac{0.5\times0.5}{(x-0.5)\times9.2}$

⇒             x =0.56 mol.

the required answer is 0.56moles.