WBJEE 2024 Chemistry Question Paper (Available)- Download Solution pdf with Answer Key

Question 1:

In the following sequence of reactions, compound 'M' is:

M → _CH3MgBr → N + CH₄ ↑ → _H⁺ CH₃COCH₂COCH₃

Options:

Question 2:

Identify the ion having 4f⁶ electronic configuration:

Options:

1. Gd³⁺
2. Sm³⁺
3. Sm²⁺
4. Tb³⁺

Question 3:

Metallic conductors and semiconductors are heated separately. What are the changes in conductivity?

Options:

1. Increase, Increase
2. Decrease, Decrease
3. Increase, Decrease
4. Decrease, Increase

Question 4:

The equivalent weight of Na₂S₂O₃ (Gram molecular weight = M) in the given reaction is:

I₂ + 2 Na₂S₂O₃ → 2 NaI + Na₂S₄O₆

Options:

1. M/2
2. M
3. 2M
4. M/4

Question 5:

The reactivity order of the following molecules towards SN1 reaction is:

Allyl chloride (I), Chlorobenzene (II), Ethyl chloride (III)

Options:

1. I > II > III
2. I > III > II
3. II > I > III
4. III > I > II

Question 6:

Toluene reacts with mixed acid at 25°C to produce:

Options:

1. Nearly equal amounts of o- and m-nitrotoluene
2. p-Nitrotoluene (only)
3. Predominantly o-nitrotoluene and p-nitrotoluene
4. 2, 4, 6-Trinitrotoluene (only)

Question 7:

The product 'P' in the above reaction is:

→ _{CH3CH2C(O)ONa (anhydrous)} → P

Options:

1. Ph CH = CHCH₂COOH

Correct Answer: 2.
View Solution

Question 8:

The decreasing order of reactivity of the following alkenes towards HBr addition is:

CH₃–CH=CH₂ (I), CF₃–CH=CH₂ (II), MeOCH=CH₂ (III), (IV)

Options:

1. I > II > III > IV
2. II > IV > I > III
3. III > IV > I > II
4. III > I > II > IV

Question 9:

Ozonolysis of o-xylene produces:

Options:

1. I:III = 1:2
2. II:III = 2:1
3. I:II:III = 1:2:3
4. I:II:III = 3:2:1

Question 10:

The compounds A and B are respectively:

Options:

Correct Answer:3.
View Solution

Question 11:

The compound that does not give a positive test for nitrogen in Lassaigne's test is:

Options:

Correct Answer: 2.
View Solution

Question 12:

The correct acidity order of phenol (I), 4-hydroxybenzaldehyde (II), and 3-hydroxybenzaldehyde (III) is:

Options:

1. I < II < III
2. I < III < II
3. II < I < III
4. III < I < II

Question 13:

The major product of the following reaction is:

Options:

Correct Answer: 3.
View Solution

Question 14:

Which of the following statements is correct for a spontaneous polymerization reaction?

Options:

1. ΔG < 0, ΔH < 0, ΔS < 0
2. ΔG < 0, ΔH > 0, ΔS > 0
3. ΔG > 0, ΔH < 0, ΔS > 0
4. ΔG > 0, ΔH > 0, ΔS > 0

Question 15:

At 25°C, the ionic product of water is 10^-14. The free energy change for the self-ionization of water in kcal mol^-1 is:

Options:

1. 20.5
2. 14.0
3. 19.1
4. 25.3

Question 16:

Consider an electron moving in the first Bohr orbit of a He⁺ ion with a velocity v₁. If it is allowed to move in the third Bohr orbit with a velocity v₃, indicate the correct v₃ : v₁ ratio:

Options:

1. 3:1
2. 2:1
3. 1:3
4. 1:2

Question 17:

The compressibility factor for a van der Waals gas at high pressure is:

Options:

1. 1 + RT/Pb
2. 1 + Pb/RT
3. 1 - Pb/RT
4. 1

Question 18:

For a spontaneous process, the incorrect statement is:

Options:

1. (ΔG_system)_{T, P} > 0
2. (ΔS_system) + (ΔS_surroundings) > 0
3. (ΔG_system)_{T, P} < 0
4. (ΔU_system)_{S, V} < 0

Question 19:

Identify the incorrect statement among the following:

Options:

1. Viscosity of liquid always decreases with increase in temperature.
2. Surface tension of liquid always decreases with increase in temperature.
3. Viscosity of liquid always increases in presence of impurity.
4. Surface tension of liquid always increases in presence of impurity.

Question 20:

Which of the following statements is true about the equilibrium constant and rate constant of a single-step chemical reaction?

Options:

1. Equilibrium constant may increase or decrease, but rate constant always increases with temperature.
2. Both equilibrium constant and rate constant increase with temperature.
3. Rate constant may increase or decrease, but equilibrium constant always increases with temperature.
4. Both equilibrium constant and rate constant decrease with temperature.

Question 21:

After the emission of a β-particle followed by an α-particle from ²¹⁴₈₃Bi, the number of neutrons in the atom is:

Options:

1. 210
2. 128
3. 129
4. 82

Question 22:

Which hydrogen-like species will have the same radius as the 1st Bohr orbit of a hydrogen atom?

Options:

1. n=2, Li²⁺
2. n=2, Be³⁺
3. n=2, He⁺
4. n=3, Li²⁺

Question 23:

For a first-order reaction with rate constant k, the slope of the plot of log(reactant concentration) against time is:

Options:

1. k/2.303
2. k
3. -k/2.303
4. -k

Question 24:

Equal volumes of aqueous solution of 0.1 M HCl and 0.2 M H₂SO₄ are mixed. The concentration of H⁺ ions in the resulting solution is:

Options:

1. 0.15 M
2. 0.30 M
3. 0.10 M
4. 0.25 M

Question 25:

The correct order of boiling points of the given aqueous solutions is:

Options:

1. 1 N KNO₃ > 1 N NaCl > 1 N CH₃COOH > 1 N sucrose
2. 1 N KNO₃ = 1 N NaCl > 1 N CH₃COOH > 1 N sucrose
3. Same for all
4. 1 N KNO₃ = 1 N NaCl = 1 N CH₃COOH > 1 N sucrose

Question 26:

Correct solubility order of AgF, AgCl, AgBr, AgI in water is:

Options:

1. AgF < AgCl > AgBr > AgI
2. AgI < AgBr < AgCl < AgF
3. AgF < AgCl < AgBr < AgI
4. AgCl > AgBr > AgF > AgI

Question 27:

What will be the change in acidity if: (i) CuSO₄ is added to saturated (NH₄)₂SO₄ solution, (ii) SbF₅ is added to anhydrous HF?

Options:

1. Increases, Increases
2. Decreases, Decreases
3. Increases, Decreases
4. Decreases, Increases

Question 28:

Which of the following contains the maximum number of lone pairs on the central atom?

Options:

1. ClO₃^-
2. XeF₄
3. SF₄
4. I₃^-

Question 29:

Number of moles of ions produced by the complete dissociation of one mole of Mohr's salt in water is:

Options:

1. 3
2. 4
3. 5
4. 6

Question 30:

Which of the following species exhibits both LMCT and paramagnetism?

Options:

1. MnO₄^-
2. MnO₄^2-
3. Cr₂O₇^2-
4. CrO₄^2-

Question 31:

How many P–O–P linkages are there in P₄O₁₀?

Options:

1. Six
2. Four
3. Five
4. One

Question 32:

Q and R in the reaction sequences are respectively:

Options:

1. Hg(OAc)₂, NaBH₄/OH^-; B₂H₆, H₂O₂/OH^-
2. B₂H₆, H₂O₂/OH^-; H⁺/H₂O
3. Hg(OAc)₂, NaBH₄/OH^-; H⁺/H₂O
4. B₂H₆, H₂O₂/OH^-; Hg(OAc)₂, NaBH₄/OH^-

Question 33:

pH of 10^-8 M HCl solution is:

Options:

1. 8
2. Greater than 7, less than 8
3. Greater than 8
4. Greater than 6, less than 7

Question 34:

The degree of dissociation of acetic acid is:

Options:

1. 0.021
2. 0.21
3. 0.012
4. 0.12

Question 35:

The number(s) of -OH group(s) present in H₃PO₃ and H₃PO₄ is/are:

Options:

1. 3 and 3 respectively
2. 3 and 4 respectively
3. 2 and 3 respectively
4. 1 and 3 respectively

Question 36:

Which of the following statements about the SN2 reaction mechanism is/are true?

Options:

1. The rate of reaction increases with increasing nucleophilicity.
2. The number 2 denotes a second-order reaction.
3. Tertiary butyl substrates do not follow this mechanism.
4. The optical rotation of substrates always changes from (+) to (-) or from (-) to (+) in the products.

Question 37:

Which of the following represent(s) the enantiomer of Y?

Options:

Question 38:

Identify the correct statement(s):

Options:

1. The oxidation number of Cr in CrO₅ is +6.
2. ΔH > ΔU for the reaction N₂O₄(g) → 2 NO₂(g), provided both gases behave ideally.
3. pH of 0.1 N H₂SO₄ is less than that of 0.1 N HCl at 25°C.
4. RT/F = 0.0591 V at 25°C.

Question 39:

Which of the following ion/ions is/are diamagnetic?

Options:

1. [CoF₆]^3-
2. [Co(NH₃)₆]³⁺
3. [Fe(OH₂)₆]²⁺
4. [Fe(CN)₆]^4-

Question 40:

Which of the following statement(s) is/are correct?

Options:

1. Solid I₂ is freely soluble in water.
2. Solid I₂ is freely soluble in water but only in the presence of excess KI.
3. Solid I₂ is freely soluble in CCl₄.
4. Solid I₂ is freely soluble in hot water.