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MHT CET202520 Apr 2025Evening ShiftChemistryChemical KineticsActual

What is order and molecularity of following reaction? NO _ 2( ~g ) + NO _ 2( ~g ) 2 NO _ ( g ) + O _ 2( ~g )

Options

  1. Aorder 1, molecularity 2
  2. Border 2, molecularity 2
  3. Corder 2, molecularity 3
  4. Dorder zero, molecularity 2

Correct answer

B. order 2, molecularity 2

Step-by-step solution

Molecularity refers to the number of reacting species involved in an elementary step. In this reaction, two NO ₂ molecules collide, so the molecularity is 2. For elementary reactions, the order equals molecularity with rate law determined directly from stoichiometry. The reaction 2 NO _ 2( g ) 2 NO _ ( g ) + O _ 2( g ) implies Rate = k[ NO ₂]^2 , making the order 2. Since both order and molecularity are 2, the correct choice is B .

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