JEE Main · 2025 · Shift-IIeasyCK-143

Consider the elementary reaction {A(g) + B(g)} {C(g) + D(g)} If the volume of reaction mixture is suddenly reduced to…

Chemical Kinetics · Class 12 · JEE Main Previous Year Question

Question

Consider the elementary reaction

A(g) + B(g)→C(g) + D(g)\text{A(g) + B(g)} \rightarrow \text{C(g) + D(g)}

If the volume of reaction mixture is suddenly reduced to 13\tfrac{1}{3} of its initial volume, the reaction rate will become 'xx' times of the original reaction rate. The value of xx is:

Options
  1. a

    19\tfrac{1}{9}

  2. b

    99

    ✓
  3. c

    13\tfrac{1}{3}

  4. d

    33

Correct Answerb

99

Detailed Solution

Step 1 — Rate law for elementary reaction:

R1=k[A][B]=k⋅nAV⋅nBVR_1 = k[\text{A}][\text{B}] = k\cdot\tfrac{n_A}{V}\cdot\tfrac{n_B}{V}

Step 2 — Volume reduced to 13V\tfrac{1}{3}V, so concentrations become 3×:

R2=k⋅3nAV⋅3nBV=9R1R_2 = k\cdot\tfrac{3n_A}{V}\cdot\tfrac{3n_B}{V} = 9R_1

Answer: (b) x=9x = 9

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