The rate of effusion of a gas depends on:

The correct answer is C: Temperature and inverse square root of molar mass. According to Graham's law, rate of effusion is proportional to √(T/M). Both temperature and molar mass affect effusion rate. Higher T increases molecular velocity; higher M decreases it.

Which of the following represents the correct relationship between Qc and Kc for a reaction at non-equilibrium?

The correct answer is C: If Qc = Kc, reaction is at equilibrium. Qc = Kc indicates equilibrium. If Qc > Kc, reaction shifts backward; if Qc < Kc, reaction shifts forward.

In the nitration of toluene, the ortho and para isomers are major products because the methyl group is:

The correct answer is B: Electron-donating and ortho/para-directing. The methyl group is electron-donating through inductive and hyperconjugative effects, making the benzene ring more electron-rich. This activates the ring for EAS and directs incoming electrophiles to ortho and para positions.

Which of the following carboxylic acids is most acidic?

The correct answer is B: CF3-COOH. CF3-COOH is most acidic because fluorine is highly electronegative and strongly withdraws electron density through inductive effects, stabilizing the conjugate base carboxylate ion.

In the reaction 2KMnO₄ + 16HCl → 2KCl + 2MnCl₂ + 5Cl₂ + 8H₂O, the reducing agent is:

The correct answer is B: HCl. In this reaction, HCl acts as a reducing agent because Cl⁻ (oxidation state -1) is oxidized to Cl₂ (oxidation state 0). Mn in KMnO₄ is reduced from +7 to +2.

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JEE Chemistry
Chemical Kinetics

Chemistry questions for JEE Main — Physical, Organic, Inorganic Chemistry.

26 Q 5 Topics Take Mock Test

Difficulty: All Easy Medium Hard 21–26 of 26

Topics in JEE Chemistry

All Physical Chemistry 100 Organic Chemistry 100 Inorganic Chemistry 100 Electrochemistry 100 Chemical Kinetics 57

Q.21 Medium Chemical Kinetics

At 300 K, a reaction has a half-life of 10 minutes. At 310 K, the half-life becomes 5 minutes. What is the approximate value of temperature coefficient (assuming RRT ≈ 2)?

A 1.5

B 2.0

C 2.5

D 3.0

Correct Answer: B. 2.0

EXPLANATION

For a first-order reaction, if half-life decreases from 10 to 5 minutes (becomes half) with a 10 K increase, this indicates the reaction rate doubles per 10 K, giving a temperature coefficient of 2.

Test

Q.22 Medium Chemical Kinetics

For the reaction A → B, the integrated rate law for zero-order kinetics is:

A [A] = [A]₀ - kt

B ln[A] = ln[A]₀ - kt

C 1/[A] = 1/[A]₀ + kt

D [A]² = [A]₀² - kt

Correct Answer: A. [A] = [A]₀ - kt

EXPLANATION

For zero-order reaction: d[A]/dt = -k, integrating gives [A] = [A]₀ - kt, which is a linear equation.

Test

Q.23 Medium Chemical Kinetics

According to Arrhenius equation, k = Ae^(-Eₐ/RT), a catalyst increases reaction rate by:

A Increasing the frequency factor A

B Decreasing the activation energy Eₐ

C Increasing the temperature T

D Decreasing the pre-exponential factor

Correct Answer: B. Decreasing the activation energy Eₐ

EXPLANATION

A catalyst provides an alternative reaction pathway with lower activation energy, thus increasing the rate constant k without affecting A or T.

Test

Q.24 Medium Chemical Kinetics

Which of the following graphs represents a first-order reaction?

A Plot of [A] vs t is linear

B Plot of ln[A] vs t is linear

C Plot of 1/[A] vs t is linear

D Plot of [A]² vs t is linear

Correct Answer: B. Plot of ln[A] vs t is linear

EXPLANATION

For a first-order reaction, ln[A] = ln[A]₀ - kt, so a plot of ln[A] vs t gives a straight line with slope -k.

Test

Q.25 Medium Chemical Kinetics

The mechanism of a reaction is: Step 1: A + B → C (slow), Step 2: C + D → E + F (fast). What is the overall reaction and the rate law?

A A + B + D → E + F; rate = k[A][B]

B A + B + D → E + F; rate = k[C][D]

C A + B + C + D → E + F; rate = k[A][B][D]

D A + B → E + F; rate = k[A]²[B]

Correct Answer: A. A + B + D → E + F; rate = k[A][B]

EXPLANATION

The overall reaction is obtained by adding all steps and canceling intermediates: A + B + D → E + F. Rate law is determined by the slow step: rate = k[A][B]

Test

Q.26 Medium Chemical Kinetics

For a first-order reaction, if the initial concentration is [A]₀ = 0.5 M and after 30 seconds it becomes 0.25 M, what is the rate constant?

A 0.0231 s⁻¹

B 0.0115 s⁻¹

C 0.0462 s⁻¹

D 0.0577 s⁻¹

Correct Answer: A. 0.0231 s⁻¹

EXPLANATION

Using ln([A]₀/[A]ₜ) = kt, ln(0.5/0.25) = k × 30, ln(2) = k × 30, k = 0.693/30 = 0.0231 s⁻¹

Test

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