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N2O5 decomposes to NO2 and O2 and follows first order kinetics. After 50 minutes, the pressure inside the vessel increases from 50 mm Hg to 87.5 mm Hg. The pressure of the gaseous mixture after 100 minutes at constant temperature will be ________. [JEE-Main On line-2018]
- (A) 136.25 mm Hg
- (B) 106.25 mm Hg
- (C) 175.0 mm Hg
- (D) 116.25 mm Hg
Correct answer: (B) 106.25 mm Hg
Solution
For N2O5 -> 2NO2 + 1/2 O2, total pressure = P0 + (3/2)x where x is N2O5 decomposed. At 50 min total=87.5 gives x=25 (half of 50), so t(1/2)=50 min. After 100 min (two half-lives) x=37.5, total = 50 + (3/2)(37.5) = 106.25 mm Hg.
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