The correct order of reducing power of Group 17 hydrides is:

The correct answer is B: HI > HBr > HCl > HF. Reducing power increases with increasing size of halogen (decreasing electronegativity). HI is the strongest reducing agent due to the weak H-I bond.

Which of the following compounds shows maximum lattice energy?

The correct answer is B: MgO. MgO has the highest lattice energy due to smallest cation (Mg²⁺) and anion (O²⁻) sizes combined with higher charges. Order: MgO > NaCl > CaO > KCl.

A 0.50 M solution of a weak acid HA has pH 2.5. Calculate Ka. (log 3.16 = 0.5)

The correct answer is D: 2.0 × 10⁻⁵. pH = 2.5, so [H⁺] = 10⁻²·⁵ = 3.16 × 10⁻³ M. Ka = [H⁺]²/[HA] = (3.16 × 10⁻³)²/(0.50 - 3.16 × 10⁻³) ≈ 2.0 × 10⁻⁵

The spin-only magnetic moment of Fe²⁺ in its ground state is approximately:

The correct answer is B: 4.90 BM. Fe²⁺ has 4 unpaired electrons (d⁶ configuration). Magnetic moment = √[n(n+2)] = √[4×6] = 4.90 BM

The standard electrode potential for Zn²⁺/Zn is -0.76 V. In a galvanic cell combining Zn and Cu electrodes, Zn will act as:

The correct answer is B: Anode (negative electrode). Zn has lower (more negative) reduction potential than Cu, making it more easily oxidized. It acts as the anode (negative electrode) in the galvanic cell.

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JEE Chemistry

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

225 Q 5 Topics Take Mock Test

Difficulty: All Easy Medium Hard 1–10 of 225

Topics in JEE Chemistry

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

Q.1 Medium Chemical Kinetics

The half-life of a second-order reaction is 100 s when initial concentration is 0.5 M. What is the rate constant?

A 0.04 M⁻¹s⁻¹

B 0.02 M⁻¹s⁻¹

C 0.2 M⁻¹s⁻¹

D 0.01 M⁻¹s⁻¹

Correct Answer: A. 0.04 M⁻¹s⁻¹

EXPLANATION

For second-order: t₁/₂ = 1/(k[A]₀); 100 = 1/(k × 0.5); k = 0.04 M⁻¹s⁻¹

Test

Q.2 Medium Chemical Kinetics

The integrated rate law for second-order reaction is 1/[A] = 1/[A]₀ + kt. If [A]₀ = 0.5 M, k = 0.4 M⁻¹s⁻¹, find [A] after 5 seconds

A 0.2 M

B 0.25 M

C 0.1 M

D 0.15 M

Correct Answer: B. 0.25 M

EXPLANATION

1/[A] = 2 + 0.4(5) = 2 + 2 = 4; [A] = 1/4 = 0.25 M

Test

Q.3 Medium Chemical Kinetics

Which statement about potential energy diagrams is CORRECT?

A Higher activation energy means faster reaction

B An exothermic reaction has ΔH > 0

C Activation energy is always greater than ΔH

D Catalyst changes activation energy but not ΔH

Correct Answer: D. Catalyst changes activation energy but not ΔH

EXPLANATION

Catalyst lowers Eₐ (forward and reverse) without changing ΔH, reaction enthalpy change

Test

Q.4 Medium Chemical Kinetics

For an elementary reaction: 2A + B → Products, the rate law is:

A Rate = k[A][B]

B Rate = k[A]²[B]

C Rate = k[A][B]²

D Rate = k[A]³[B]

Correct Answer: B. Rate = k[A]²[B]

EXPLANATION

For elementary reactions, rate law exponents = stoichiometric coefficients. Rate = k[A]²[B]

Test

Q.5 Medium Chemical Kinetics

In the reaction A → Products, doubling [A] increases rate by 4 times. The order of reaction is:

A Zero

B First

C Second

D Third

Correct Answer: C. Second

EXPLANATION

If doubling concentration increases rate by 4 times (2²), reaction is second order

Test

Q.6 Medium Chemical Kinetics

The decomposition of N₂O₅ is a first-order reaction. If 50% decomposes in 30 minutes, what is the rate constant?

A 0.023 min⁻¹

B 0.035 min⁻¹

C 0.052 min⁻¹

D 0.069 min⁻¹

Correct Answer: A. 0.023 min⁻¹

EXPLANATION

For first-order: k = 0.693/t₁/₂ = 0.693/30 = 0.0231 min⁻¹ ≈ 0.023 min⁻¹

Test

Q.7 Medium Chemical Kinetics

At 25°C, the rate constant is 3 × 10⁻² s⁻¹ and at 35°C it is 6 × 10⁻² s⁻¹. What is the temperature coefficient (Q₁₀) for this reaction?

A 1.5

B 2

C 3

D 4

Correct Answer: B. 2

EXPLANATION

Q₁₀ = k(T+10)/k(T) = (6 × 10⁻²)/(3 × 10⁻²) = 2. For typical reactions, Q₁₀ = 2-3

Test

Q.8 Medium Chemical Kinetics

The rate law for a reaction is Rate = k[A]¹[B]⁰. If [B] is doubled and [A] is halved, how does the rate change?

A Increases by factor of 2

B Decreases by factor of 2

C Remains same

D Increases by factor of 4

Correct Answer: B. Decreases by factor of 2

EXPLANATION

Rate depends only on [A] (order = 1 w.r.t. A). Halving [A] decreases rate by factor of 2. [B] has no effect

Test

Q.9 Medium Chemical Kinetics

The rate constant of a reaction increases from 4 × 10⁻³ s⁻¹ to 8 × 10⁻³ s⁻¹ when temperature increases from 300K to 310K. Calculate activation energy (R = 8.314 J/mol·K)

A 50.4 kJ/mol

B 60.8 kJ/mol

C 75.2 kJ/mol

D 85.6 kJ/mol

Correct Answer: A. 50.4 kJ/mol

EXPLANATION

Using ln(k₂/k₁) = (Eₐ/R)(T₂-T₁)/(T₁T₂); ln(2) = (Eₐ/8.314)(10/93000); Eₐ ≈ 50.4 kJ/mol

Test

Q.10 Medium Chemical Kinetics

The pre-exponential factor (A) in the Arrhenius equation is related to:

A Only the number of collisions

B Only the proper orientation of reactant molecules

C The number of collisions with proper orientation and energy distribution

D The activation energy only

Correct Answer: C. The number of collisions with proper orientation and energy distribution

EXPLANATION

The pre-exponential factor accounts for collision frequency, proper orientation (steric factor), and the Maxwell-Boltzmann energy distribution of molecules

Test

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