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NEET CHEMISTRYChemical KineticsEasy

Question

If the concentration of a solution is changed from 0.2 to 0.4, then what will be the rate and rate constant? The reaction is of first order and rate constant is k=1×106k = 1 \times 10^{-6}:

A

2×107 ; 1×1062 \times 10^{-7} \text{ ; } 1 \times 10^{-6}

B

1×107 ; 1×1061 \times 10^{-7} \text{ ; } 1 \times 10^6

C

4×107 ; 1×1064 \times 10^{-7} \text{ ; } 1 \times 10^{-6}

D

2×103 ; 1×1032 \times 10^{-3} \text{ ; } 1 \times 10^{-3}

Step-by-Step Solution

For a first-order reaction, the rate law is given by Rate=k[A]\text{Rate} = k[A]. Substituting the given values, where the rate constant k=1×106k = 1 \times 10^{-6} and the new concentration [A]=0.4[A] = 0.4, we get Rate=(1×106)×0.4=4×107\text{Rate} = (1 \times 10^{-6}) \times 0.4 = 4 \times 10^{-7}. The rate constant of a reaction is independent of the concentration of the reactants (it depends only on temperature and the presence of a catalyst). Therefore, it remains unchanged at 1×1061 \times 10^{-6}.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Chemical Kinetics. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYChemical Kineticsconcentrationsolutionchangedconstantreaction

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