Chemistry Verified Solutions
JEE Main 2025 — 28 January 2025 (Chemistry) Solutions
Step-by-step Chemistry explanations, formulas used, alternative methods, and practice mode for 28 January 2025 (Shift 1).
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Chemistry Questions (25 Questions)
Practice Mode InteractiveQ26chemistryCoordination Compounds• Class 12
EasyMCQ
According to Crystal Field Theory, the spin-only magnetic moments of [CoF₆]³⁻ and [Fe(CN)₆]³⁻ (in Bohr Magnetons, BM) are respectively: [Atomic numbers: Fe = 26, Co = 27]
A
4.90 BM and 1.73 BM
B
0 BM and 5.92 BM
C
4.90 BM and 5.92 BM
D
3.87 BM and 1.73 BM
Official Key:A
Q27chemistryAldehydes, Ketones & Carboxylic Acids• Class 12
EasyMCQ
When Benzaldehyde (C₆H₅CHO) is treated with concentrated NaOH solution (50%), the products formed are:
A
Benzyl alcohol and Sodium benzoate
B
Benzoic acid and Benzene
C
Cinnamic acid and Sodium phenoxide
D
Hydrobenzamide and Sodium formate
Official Key:A
Q28chemistryChemical Bonding & Molecular Structure• Class 11
EasyMCQ
According to Molecular Orbital Theory (MOT), which of the following species has a bond order of 2.5 and is paramagnetic?
A
N₂⁺
B
O₂²⁻
C
C₂
D
N₂
Official Key:A
Q29chemistryElectrochemistry & Redox Reactions• Class 12
EasyMCQ
The standard reduction potentials of three metals X, Y, and Z are E°(X²⁺/X) = -0.76 V, E°(Y²⁺/Y) = +0.34 V, and E°(Z²⁺/Z) = -2.37 V. The correct order of their reducing power is:
A
Z > X > Y
B
Y > X > Z
C
X > Y > Z
D
Z > Y > X
Official Key:A
Q30chemistryGeneral Organic Chemistry (GOC)• Class 11
EasyMCQ
Which of the following carbocations is the MOST stable due to resonance and hyperconjugation?
A
(C₆H₅)₃C⁺ (Triphenylmethyl carbocation)
B
(CH₃)₃C⁺ (tert-Butyl carbocation)
C
C₆H₅CH₂⁺ (Benzyl carbocation)
D
(CH₃)₂CH⁺ (Isopropyl carbocation)
Official Key:A
Q31chemistryChemical Bonding & Molecular Structure• Class 11
EasyMCQ
The shape and hybridisation of XeF₄ molecule according to VSEPR theory are respectively:
A
Square Planar, sp³d²
B
Tetrahedral, sp³
C
See-saw, sp³d
D
Octahedral, sp³d²
Official Key:A
Q32chemistryAldehydes, Ketones & Carboxylic Acids• Class 12
EasyMCQ
Which of the following compounds will give a positive Iodoform test upon treatment with I₂ and NaOH?
A
Ethanol (CH₃CH₂OH)
B
Methanol (CH₃OH)
C
Benzophenone (C₆H₅COC₆H₅)
D
3-Pentanone (CH₃CH₂COCH₂CH₃)
Official Key:A
Q33chemistryd- and f-Block Elements• Class 12
EasyMCQ
Lanthanoid contraction is primarily caused by:
A
Poor shielding effect of 4f electrons
B
Effective shielding of 5d electrons
C
Decreasing nuclear charge
D
Inert pair effect
Official Key:A
Q34chemistryChemical & Ionic Equilibrium• Class 11
EasyMCQ
For the reaction N₂(g) + 3H₂(g) ⇌ 2NH₃(g), the relation between equilibrium constants K_p and K_c is:
A
K_p = K_c (RT)⁻²
B
K_p = K_c (RT)²
C
K_p = K_c (RT)⁻¹
D
K_p = K_c
Official Key:A
Q35chemistryClassification of Elements & Periodicity• Class 11
EasyMCQ
Which of the following oxides is AMPHOTERIC in nature?
A
Al₂O₃
B
Na₂O
C
SO₃
D
CaO
Official Key:A
Q36chemistryAmines & Nitrogen Containing Compounds• Class 12
ModerateMCQ
An organic compound reacts with Hinsberg’s reagent (Benzenesulphonyl chloride) to give a precipitate that is SOLUBLE in alkali (aqueous KOH). The compound is a:
A
Primary amine (1° amine)
B
Secondary amine (2° amine)
C
Tertiary amine (3° amine)
D
Quaternary ammonium salt
Official Key:A
Q37chemistryp-Block Elements• Class 12
EasyMCQ
The correct order of increasing thermal stability of Group 16 hydrides (H₂O, H₂S, H₂Se, H₂Te) is:
A
H₂Te < H₂Se < H₂S < H₂O
B
H₂O < H₂S < H₂Se < H₂Te
C
H₂S < H₂O < H₂Te < H₂Se
D
H₂Se < H₂Te < H₂S < H₂O
Official Key:A
Q38chemistryPolymers & Biomolecules• Class 12
EasyMCQ
Which of the following polymers is a BIODEGRADABLE polyamide?
A
Nylon-2-nylon-6
B
Nylon-6,6
C
Dacron (Terylene)
D
Bakelite
Official Key:A
Q39chemistrySolutions & Colligative Properties• Class 12
EasyMCQ
For an ideal solution obeying Raoult’s law, which of the following thermodynamic properties is ZERO?
A
Both ΔH_mix = 0 and ΔV_mix = 0
B
ΔS_mix = 0
C
ΔG_mix = 0
D
Only ΔH_mix = 0
Official Key:A
Q40chemistryAmines & Nitrogen Containing Compounds• Class 12
EasyMCQ
In the Gabriel Phthalimide Synthesis, which type of amine CANNOT be prepared?
A
Aromatic primary amines (Aniline)
B
Aliphatic primary amines
C
Methylamine
D
Ethylamine
Official Key:A
Q41chemistryElectrochemistry & Redox Reactions• Class 11
ModerateMCQ
The oxidation state of Chromium in CrO₅ (Chromium peroxide) and Potassium dichromate (K₂Cr₂O₇) are respectively:
A
+6 and +6
B
+10 and +6
C
+6 and +3
D
+4 and +6
Official Key:A
Q42chemistryCoordination Compounds• Class 12
ModerateMCQ
Which of the following compounds exhibits OPTICAL ISOMERISM (Chirality)?
A
[Co(en)₃]³⁺
B
trans-[Co(NH₃)₄Cl₂]⁺
C
[Pt(NH₃)₂Cl₂]
D
[Ni(CO)₄]
Official Key:A
Q43chemistryAlcohols, Phenols & Ethers• Class 12
EasyMCQ
Phenol upon distillation with Zinc dust (Zn dust) gives:
A
Benzene
B
Toluene
C
Benzoic acid
D
Diphenyl
Official Key:A
Q44chemistryChemical & Ionic Equilibrium• Class 11
ModerateMCQ
The pH of a 10⁻⁸ M aqueous solution of HCl at 25°C is:
A
Between 6.9 and 7.0 (Slightly acidic, ~6.96)
B
8.0
C
7.0
D
6.0
Official Key:A
Q45chemistryPolymers & Biomolecules• Class 12
EasyMCQ
Which of the following amino acids is an ESSENTIAL amino acid that cannot be synthesized by the human body?
A
Valine
B
Glycine
C
Alanine
D
Glutamic acid
Official Key:A
Q46chemistryChemical Kinetics• Class 12
EasyNumerical
A first order reaction is 50% complete in 20 minutes at 300 K. The time required for 75% completion of the same reaction at 300 K (in minutes) is:
Official Key:40
Q47chemistrySolutions & Colligative Properties• Class 12
ModerateNumerical
The depression in freezing point for a 0.1 molal aqueous solution of a monobasic weak acid HA (degree of dissociation α = 0.20) is (in K, rounded to two decimal places): [Given K_f for water = 1.86 K·kg/mol]
Official Key:0.22
Q48chemistryCoordination Compounds• Class 12
EasyNumerical
The spin-only magnetic moment of [Mn(H₂O)₆]²⁺ complex ion is equal to (in Bohr Magnetons, BM, rounded to two decimal places): [Atomic number of Mn = 25]
Official Key:5.92
Q49chemistryChemical Thermodynamics & Energetics• Class 11
EasyNumerical
For the reaction 2NO₂(g) ⇌ N₂O₄(g), the value of ΔH° is -57.2 kJ/mol and ΔS° is -175 J/(K·mol). The temperature (in Kelvin, rounded to nearest integer) at which the reaction attains equilibrium (ΔG° = 0) is:
Official Key:327
Q50chemistryElectrochemistry & Redox Reactions• Class 12
EasyNumerical
How many FARADAYS of electricity are required for the complete reduction of 1 mole of MnO₄⁻ to Mn²⁺ in acidic medium?
Official Key:5