Exams › JEE Main › Chemistry
A first order reaction has a specific reaction rate of 10⁻² s⁻¹. How much time will it take for 20 g of the reactant to reduce to 5 g?
- 138.6 sec
- 346.5 sec
- 693.0 sec
- 238.6 sec
Correct answer: 346.5 sec
Solution
For a first-order reaction, the time required to reduce the concentration of the reactant by a certain factor is given by the equation: t = ln(N₀/N) / k, where N₀ is the initial concentration, N is the final concentration, and k is the rate constant. Given that the initial concentration is 20 g and the final concentration is 5 g, we can calculate the time required.
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