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JEE Main levelSingle correct optionDifficulty 2 of 3g3187

Reactant A gives products P1 and P2 in parallel, irreversible first-order reactions. $E_{a} (P1) < E_{a} (P2)$ and both pre-exponential factors are equal. On raising the temperature, the ratio $[P1] / [P2]$

Aincreases
Bdecreases but stays greater than 1
Cfalls below 1 above a certain temperature
Dremains unchanged because the pre-exponential factors are equal

Answer: B

k_{1} / k_{2} = exp [(E_{a 2} - E_{a 1}) / RT]

. The exponent is positive and shrinks as T rises, so the ratio decreases toward 1 but never goes below 1 (the exponential is always greater than 1).

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