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NEET CHEMISTRYChemical KineticsMedium

Question

If at a given instant, for the reaction 2N2O54NO2+O22N_2O_5 \rightarrow 4NO_2 + O_2 rate and rate constant are 1.02×1041.02 \times 10^{-4} and 3.4×105 sec13.4 \times 10^{-5} \text{ sec}^{-1} respectively, then the concentration of N2O5N_2O_5 at that time will be:

A

1.732 mol L11.732 \text{ mol L}^{-1}

B

3.0 mol L13.0 \text{ mol L}^{-1}

C

1.02×104 mol L11.02 \times 10^{-4} \text{ mol L}^{-1}

D

3.4×105 mol L13.4 \times 10^5 \text{ mol L}^{-1}

Step-by-Step Solution

The unit of the rate constant kk is given as sec1\text{sec}^{-1}, which indicates that the decomposition of N2O5N_2O_5 is a first-order reaction.

For a first-order reaction, the rate law is expressed as: Rate=k[N2O5]\text{Rate} = k[N_2O_5]

Given: Rate=1.02×104 mol L1 sec1\text{Rate} = 1.02 \times 10^{-4} \text{ mol L}^{-1} \text{ sec}^{-1} Rate constant, k=3.4×105 sec1k = 3.4 \times 10^{-5} \text{ sec}^{-1}

Rearranging the rate law to solve for the concentration of N2O5N_2O_5: [N2O5]=Ratek[N_2O_5] = \frac{\text{Rate}}{k} [N2O5]=1.02×1043.4×105=10.2×1053.4×105=3.0 mol L1[N_2O_5] = \frac{1.02 \times 10^{-4}}{3.4 \times 10^{-5}} = \frac{10.2 \times 10^{-5}}{3.4 \times 10^{-5}} = 3.0 \text{ mol L}^{-1}

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 Kineticsinstantreactionrightarrowconstantrespectively

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