Chemical Kinetics Important Questions for NEET Chemistry - 2026

1. Multiple choice questions.

1. The rate of a chemical reaction generally increases with increase in:

• (a) Temperature
• (b) Pressure
• (c) Concentration of reactants
• (d) All of these

Answer: (d) All of these

2. For a reaction: 2A → Products, if the concentration of A decreases from 1.0 M to 0.5 M in 10 minutes, the average rate is:

• (a) $2.5 \times 10^{-2}$ M/min
• (b) $5.0 \times 10^{-2}$ M/min
• (c) $2.0 \times 10^{-2}$ M/min
• (d) $1.0 \times 10^{-2}$ M/min

Answer: (a) $2.5 \times 10^{-2}$ M/min

3. The unit of rate constant for a first-order reaction is:

• (a) mol L^-1 s^-1
• (b) s^-1
• (c) L mol^-1 s^-1
• (d) No units

Answer: (b) s^-1

4. Which one is NOT a factor affecting the rate of a reaction?

• (a) Concentration
• (b) Temperature
• (c) Volume of vessel
• (d) Catalyst

Answer: (c) Volume of vessel

5. For the reaction 2NO₂ → 2NO + O₂, if the rate of disappearance of NO₂ is 0.02 mol L^-1s^-1, then the rate of formation of O₂ is:

• (a) 0.02 mol L^-1s^-1
• (b) 0.01 mol L^-1s^-1
• (c) 0.04 mol L^-1s^-1
• (d) 0.10 mol L^-1s^-1

Answer: (b) 0.01 mol L^-1s^-1

2. Very Short Answer (VSA).

1. Define the rate constant.

Answer: A rate constant is a proportionality constant in the rate law that relates reaction rate to reactant concentrations, for a given temperature.

2. What is meant by molecularity of a reaction?

Answer: Molecularity is the number of reactant particles taking part in an elementary reaction and undergoing simultaneous collision.

3. What is an elementary reaction?

Answer: An elementary reaction is a single-step reaction where reactants directly form products without intermediate steps.

4. State the unit of rate constant for a zero-order reaction.

Answer: The unit of rate constant for a zero-order reaction is mol L^-1 s^-1.

5. What is activation energy?

Answer: Activation energy is the minimum energy required for reactants to transform into products during a chemical reaction.

3. Short Answer Questions.

1. Explain the effect of temperature on the rate of a chemical reaction.

Answer: Increasing temperature raises the kinetic energy of molecules, causing more frequent and energetic collisions. According to the Arrhenius equation, even a small temperature rise can greatly increase reaction rate because a larger fraction of molecules exceed the activation energy barrier.

2. Define order of reaction and differentiate it from molecularity.

Answer: Order of reaction is the sum of powers to which concentration terms are raised in the rate law, determined experimentally. Molecularity refers to the number of species colliding in an elementary step. Order applies to overall reactions, molecularity only to elementary steps.

3. Derive the integrated rate law for a first-order reaction.

Answer:

1. For $A \rightarrow$ Products, rate law: $-\frac{d[A]}{dt} = k[A]$
2. $\frac{d[A]}{[A]} = -k\,dt$
3. Integrate both sides: $\int_{[A]_0}^{[A]} \frac{d[A]}{[A]} = -k \int_0^t dt$
4. $\ln\frac{[A]}{[A]_0} = -kt$
5. $\ln[A] = \ln[A]_0 - kt$

4. State the collision theory for bimolecular reactions and the role of activation energy.

Answer: Collision theory states that for a reaction to occur, reactant molecules must collide with sufficient energy and proper orientation. Only those collisions where the kinetic energy meets or exceeds the activation energy result in product formation.

5. A reaction is first order in A. If $[A]$ decreases from 0.8 M to 0.2 M in 30 minutes, calculate the rate constant.

Answer:

1. First-order: $k = \frac{2.303}{t}\log\frac{[A]_0}{[A]}$
2. $k = \frac{2.303}{30}\log\frac{0.8}{0.2}$
3. $\log(4) = 0.602$
4. $k = \frac{2.303}{30} \times 0.602$
5. $k = 0.0462$ min^-1

4. True or False Questions.

1. A zero-order reaction’s rate does not depend on the concentration of reactants.

Answer: True

2. The unit of rate constant is always the same for all reaction orders.

Answer: False

3. A catalyst increases the activation energy of a reaction.

Answer: False

4. First-order reactions have a constant half-life, irrespective of concentration.

Answer: True

3. Fill in the Blanks Questions.

1. The rate law for a zero-order reaction is Rate = _____.

Answer: k

2. The half-life $(t_{1/2})$ of a first-order reaction is given by $t_{1/2} = \frac{0.693}{_____}$.

Answer: k

3. According to Arrhenius equation, $k = A e^{-E_a/RT}$, $E_a$ is called _____.

Answer: Activation energy

4. In a first-order reaction, the unit of the rate constant is _____.

Answer: s^-1

5. The sum of the powers of concentration terms in the rate law expression is known as the _____ of reaction.

Answer: Order

Why Understanding Chemical Kinetics Helps You Excel in NEET Chemistry

Solid command over Chemical Kinetics helps NEET students answer questions about rate laws, half-life and the Arrhenius equation. This topic links theory with numericals, sharpening your problem-solving skills to meet NEET Chemistry standards.

Learn about activation energy, order of reactions and the important role of catalysts. These basics often appear in the NEET exam. Mastering these core principles means fewer surprises on test day and smoother calculation of rates, constants, and mechanisms.

By studying with Vedantu’s NEET important questions, you build confidence in Chemistry topics that matter most. Each solved problem teaches you practical shortcuts and deepens your understanding of rate laws and kinetics for quick, accurate answers in 2026.