Consider the following gas phase reaction being carried out in a closed vessel at $25^{\circ} \mathrm{C}$. $2 \mathrm{~A}(\mathrm{~g}) \rightarrow 4 \mathrm{~B}(\mathrm{~g})+\mathrm{C}(\mathrm{~g})$ | time (min) | total pressure of the system (mm Hg) | |------------|--------------------------------------| | 30 | 300 | | ∞ | 600 | The pressure of $\mathrm{C}(\mathrm{g})$ at 30 minutes time interval would be \_\_\_\_ mm Hg. (Nearest integer)

JEE Main · 2026 · 02 Apr 2026 · Shift 2 · Chemical Kinetics

Consider the following gas phase reaction being carried out in a closed vessel at

2 5^{\circ} C

2 A (g) \to 4 B (g) + C (g)

time (min)	total pressure of the system (mm Hg)
30	300
∞	600

The pressure of

C (g)

at 30 minutes time interval would be ____ mm Hg. (Nearest integer)

Answer: 20

Let the fall in the pressure of A be

p

. By the stoichiometry

2 A \to 4 B + C

the pressures of B and C rise by

2 p

and

0.5 p

, so the total pressure is

P_{0} + 1.5 p

, where

P_{0}

is the initial pressure of A. At completion all A is spent,

p = P_{0}

, giving

2.5 P_{0} = 600

and

P_{0} = 240 mm Hg

. At

30

minutes

240 + 1.5 p = 300

, so

p = 40 mm Hg

. The pressure of C is

0.5 p = 20 mm Hg

JEE Main · 2026 · 02 Apr 2026 · Shift 2 · Integer answer