Question

The equilibrium constant Kc for the decomposition
of PCI, is 0.625 mole/lit at 300°C. Then the value
of Kp is -
(A) 29.4 atm
(B) 0.0625 atm
(C) 6.25 atm
(D) 0.00625 atm
I need full solution ​

Answer 1

                   ✪ Answer ✪

The equation of decomposition of PCl$_{5}$ can be given as :

PCl$_5$ ⇆ PCl$_3$ + Cl$_2$

Note that here all the three in gaseous state.

Now, change in moles will be :

Number of final moles - number of initial moles

= 2 - 1 = 1

By formula, we know that :

✦  K$_p$ = K$_c$ $($RT$)^n$     ✦

• Where R = 0.0821 L atm mo$l^{-1}$ $K^{-1}$

• T is temperature in kelvin
• 300 celsius = (300 + 273) Kelvin = 573 Kelvin

• n is the change in moles (Here 1)

Substituting the values, we get :

K$_p$ = 0.625 $($ 0.0821 x 573 $)^1$

    = 0.625 (47.04)

    = 29.4 atm

۞ Thus, your final answer is option (A) 29.4 atm ۞