In the reduction of ketones and aldehydes using DIBAL-H, the product is:

The correct answer is B: An alcohol. DIBAL-H (Diisobutylaluminum hydride) reduces carbonyl compounds to primary alcohols (from aldehydes) or secondary alcohols (from ketones). It's milder than LiAlH4.

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?

The correct answer is A: 0.0231 s⁻¹. 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

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.

The reaction of concentrated H₂SO₄ with carbon produces primarily:

The correct answer is D: CO and SO₂ in 2:1 ratio. C + 2H₂SO₄(conc) → CO₂ + 2SO₂ + 2H₂O at 25°C. At higher temperatures: C + 2H₂SO₄(conc) → CO + 2SO₂ + 2H₂O, with CO and SO₂ in 1:1 ratio. Overall primary products are CO and SO₂.

Which of the following statements about Le Chatelier's principle is NOT correct?

The correct answer is A: Increasing pressure favours forward reaction in the given equilibrium. Increasing pressure favours the direction with fewer moles of gas. For 2NO₂ ⇌ N₂O₄, it favours forward reaction (correct), but statement A is incomplete without specifying the reaction.

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JEE Chemistry
Physical Chemistry

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

31 Q 5 Topics Take Mock Test

Difficulty: All Easy Medium Hard 31–31 of 31

Topics in JEE Chemistry

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

Q.31 Easy Physical Chemistry

Which of the following has the highest lattice energy?

A NaCl

B MgO

C KCl

D CaO

Correct Answer: B. MgO

EXPLANATION

MgO has the highest lattice energy due to smaller ionic radii of Mg²⁺ and O²⁻ ions, leading to stronger electrostatic attractions.

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