JEE Main 2022 · 29 Jun · Shift 2 · Chemistry Q64

← JEE Main 2022 · 29 Jun · Shift 2

ChemistrySingle correct+4 / -1Question 64 of 90

4.0 moles of argon and 5.0 moles of $\mathrm{PCl_5}$ are introduced into an evacuated flask of 100 litre capacity at 610 K. The system is allowed to equilibrate. At equilibrium, the total pressure of mixture was found to be 6.0 atm. The $K_p$ for the reaction is

[Given: R = 0.082 L atm K $^{-1}$ mol $^{-1}$ ]

2.25

6.24

12.13

15.24

Answer and worked solution

Official answer: A

Total moles. $\dfrac{6\times100}{0.082\times610}\approx12$ ; minus 4 Ar leaves 8, so $x=3$ of $\mathrm{PCl_5}$ dissociated.

Partial pressures (0.5 atm per mol): $\mathrm{PCl_5}$ 1, $\mathrm{PCl_3}$ and $\mathrm{Cl_2}$ 1.5 each. $K_p=\frac{1.5^2}1=2.25$ .

(A)

Topics:Law of mass action and Kc, Kp

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JEE Main 2022 · 29 Jun · Shift 2, Chemistry question 64