Chemical Kinetics: JEE Advanced PYQ, 2007–2026

Q1 · Chemistry · Chemical Kinetics

A gaseous reaction has the rate law: rate = k[A]^(3/2)[B]^(1/2). If the volume of the vessel is reduced to one quarter at constant temperature, by what factor does the rate change at that instant?

• A2
• B4
• C16
• D8

Q2 · Chemistry · Chemical Kinetics

For a reaction A → products, a plot of log₁₀(rate) against log₁₀[A] is a straight line with slope 2. It cuts the log(rate) axis at −3.0, that is, at log₁₀[A] = 0. Concentration is in mol L⁻¹ and rate is in mol L⁻¹ s⁻¹. What is the rate of the reaction when [A] = 0.10 mol L⁻¹?

• A1.0 × 10⁻⁴ mol L⁻¹ s⁻¹
• B1.0 × 10⁻⁶ mol L⁻¹ s⁻¹
• C1.0 × 10⁻³ mol L⁻¹ s⁻¹
• D1.0 × 10⁻⁵ mol L⁻¹ s⁻¹

Q3 · Chemistry · Chemical Kinetics

The gas-phase reaction A(g) → 2B(g) is carried out at constant temperature in a rigid vessel, starting with pure A at a pressure of 0.40 atm. The total pressure in the vessel is 0.60 atm after 10 min and 0.70 atm after 20 min. Assuming the reaction follows simple zero-, first- or second-order kinetics in A, what is its order?

• AZero order
• BFirst order
• CSecond order
• DThe order cannot be determined, because the total pressure rather than the partial pressure of A is measured

Q4 · Chemistry · Chemical Kinetics

The reaction NO₂(g) + CO(g) → NO(g) + CO₂(g) is believed to occur by the mechanism: Step 1 (slow): 2NO₂ → NO₃ + NO; Step 2 (fast): NO₃ + CO → NO₂ + CO₂. At constant temperature, [NO₂] is doubled and [CO] is tripled. By what factor does the rate change?

• A4
• B6
• C12
• D2

Q5 · Chemistry · Chemical Kinetics

The initial rates of the reaction A + B → products were measured at constant temperature in three experiments. Experiment 1: [A] = 0.04 M, [B] = 0.10 M, rate = 1.5 × 10⁻³ mol L⁻¹ s⁻¹. Experiment 2: [A] = 0.16 M, [B] = 0.10 M, rate = 1.2 × 10⁻² mol L⁻¹ s⁻¹. Experiment 3: [A] = 0.04 M, [B] = 0.30 M, rate = 4.5 × 10⁻³ mol L⁻¹ s⁻¹. What is the initial rate (in mol L⁻¹ s⁻¹) when [A] = 0.01 M and [B] = 0.20 M?

• A3.75 × 10⁻⁴
• B7.5 × 10⁻⁴
• C1.875 × 10⁻⁴
• D1.5 × 10⁻³

Q6 · Chemistry · Chemical Kinetics

For a reaction X + Y → Z at constant temperature, three initial-rate experiments gave: (1) [X] = 0.10 M, [Y] = 0.10 M, rate = 4.0 × 10⁻⁴ mol L⁻¹ s⁻¹; (2) [X] = 0.20 M, [Y] = 0.10 M, rate = 1.6 × 10⁻³ mol L⁻¹ s⁻¹; (3) [X] = 0.20 M, [Y] = 0.30 M, rate = 4.8 × 10⁻³ mol L⁻¹ s⁻¹. What is the initial rate, in mol L⁻¹ s⁻¹, when [X] = 0.30 M and [Y] = 0.20 M?

• A7.2 × 10⁻³
• B3.6 × 10⁻³
• C2.4 × 10⁻³
• D1.44 × 10⁻²

Q7 · Chemistry · Chemical Kinetics

The reaction A + B → products is first order in A and first order in B, so rate = k[A][B]. It is run at constant temperature with [A]₀ = 0.010 mol L⁻¹ and [B]₀ = 2.0 mol L⁻¹. The concentration of A is found to halve every 10 min throughout the run. (ln 2 = 0.693) What is the value of k?

• A0.0693 L mol⁻¹ min⁻¹
• B0.139 L mol⁻¹ min⁻¹
• C0.0347 L mol⁻¹ min⁻¹
• D10 L mol⁻¹ min⁻¹

Q8 · Chemistry · Chemical Kinetics

A substance A decomposes by two parallel first-order paths: A → B with rate constant 2 × 10⁻³ s⁻¹, and A → C with rate constant 3 × 10⁻³ s⁻¹. What percentage of the product is B?

• A40%
• B50%
• C60%
• D67%

Q9 · Chemistry · Chemical Kinetics

For a reaction A + B → products, the following initial-rate data were obtained: (i) [A] = 0.10 M, [B] = 0.10 M gives initial rate r; (ii) [A] = 0.20 M, [B] = 0.10 M gives initial rate 4r; (iii) [A] = 0.20 M, [B] = 0.40 M gives initial rate 8r. Under identical conditions, 100 mL of 0.80 M A is rapidly mixed with 100 mL of 0.80 M B (volumes additive). What is the initial rate immediately after mixing?

• A32 r
• B64 r
• C16 r
• D128√2 r ≈ 181 r

Q10 · Chemistry · Chemical Kinetics

The gas-phase reaction 2NO(g) + O₂(g) → 2NO₂(g) is elementary in its rate behaviour, with rate = k[NO]²[O₂]. The volume of the reaction vessel is suddenly reduced to one-third of its original value at constant temperature. The rate of the reaction then becomes:

• A3 times the original rate
• B9 times the original rate
• C27 times the original rate
• D1/27 of the original rate