GATE XL concept:rate-constant PYQs & Answers

Questions 1–6 of 6. Imported answers require independent review unless marked reviewed.

For product formation from only one type of reactant (e.g. A → product), the CORRECT match for the order of the reaction (given in Column I) with the half-life expression (given in Column II) is

([A]₀ is the initial concentration and kᵣ is the rate constant)

Column I: Order	Column II: Half-life expression
i. Zero	P. ln 2 / kᵣ
ii. First	Q. [A]₀ / 2kᵣ
iii. Second	R. 1 / kᵣ[A]₀
	S. 2kᵣ / [A]₀

Your answerChoose one option.

i–R, ii–P, iii–S

i–Q, ii–P, iii–R

i–S, ii–R, iii–Q

i–Q, ii–P, iii–S

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Consider a second order reaction,

The concentration of A is represented as [A].

Which of the following is the CORRECT plot for determining the rate constant for the above reaction?

Your answerChoose one option.

Diagram for Life Sciences question 11 (figure 2)

Diagram for Life Sciences question 11 (figure 3)

Diagram for Life Sciences question 11 (figure 4)

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A molecule in solution crystallizes into two different crystal forms with rate constants of 0.02 s

and 0.13 s

. If the crystallization is assumed to be under kinetic control, then the half-life (in seconds, rounded off to one decimal place) of the molecule is _________.

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The activation energy (

) estimated for a reaction from the Arrhenius equation is 21 kJ mol

. If the frequency factor is assumed to be independent of temperature, then the ratio of the rate constants determined at 298 K and 260 K is ________ (rounded off to two decimal places). (Given: Gas constant, R = 8.315 J K

mol

)

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For the reaction mechanism,

;

. For this step, assume

: rate constant for this step. The rate law is

Your answerChoose one option.

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The activation energy (Eₐ) values for two reactions carried out at 25 °C differ by 5.0 kJ mol⁻¹. If the pre-exponential factors (A₁ and A₂) for these two reactions are of the same magnitude, the ratio of rate constants (k₁/k₂) is ______ (up to two decimal places). (Given: Gas constant R = 8.314 J K⁻¹ mol⁻¹)

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GATE XL concept:rate-constant PYQs

How to practice concept:rate-constant

Question 21

Question 11

Question 12

Question 14

Question 6

Question 14