If 50 % of a reaction occurs in 100 second and 75 % of the reaction occurs in 200 second, the order of this reaction is:

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Quantrex Academy · Accepted Answer

Correct answer: D. 1

50% of a reaction occurs in 100 second and 75% of the reaction occurs in 200 second, the order of this reaction is 1.
Let the initial reactant concentration is 1 M.
In the first 100 seconds, reactant concentration is reduced to $50 % or1 \times \dfrac{50}{100} = 0 . 5M .$
In the second 100 seconds (total 200 seconds from start), reactant concentration is reduced to $100 - 75 = 25 % or1 \times \dfrac{25}{100} = 0 . 25M .$ .
Thus, we observe that after each 100 second period, the reactant concentration is reduced to one half. Hence, 100 seconds is the half-life period and is independent of reactant concentration. This is characteristic of the first-order reaction.

First-order reaction as the half-life is constant.

If 50 % of a reaction occurs in 100 second and 75 % of the reaction...

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