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JEE Main20264 April 2026Evening ShiftChemistryChemical KineticsActual

Consider the given graph showing variation of reactant concentration with time. Three different reactions were started with identical initial concentration of reactants. Which of the following statement is correct?

Options

  1. AThe order of all the three reactions is same.
  2. BThe rate constant of reaction 3 is larger than the rate constant of reaction 2 if the order of reaction is sam
  3. CThe SI unit of rate constant of reaction 1 is s ⁻¹ .
  4. DThermal decomposition of HI on gold surface is an example of reaction 2 .

Correct answer

B. The rate constant of reaction 3 is larger than the rate constant of reaction 2 if the order of reaction is sam

Step-by-step solution

Analysis of the graph: The graph shows reactant concentration [R] vs time t for three reactions starting from the same initial concentration. Curve 1 is a straight line with negative slope. For a zero-order reaction, the integrated rate law is [R] = [R]₀ - kt , which is a straight line in [R] vs t . Hence, reaction 1 is a zero-order reaction. Curves 2 and 3 are non-linear (exponential-type decays), so they correspond to reactions of order greater than zero (e.g., first or second order). Evaluating the options: (1)

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