NEET 2022 Chemistry Questions with Solutions

Explanation

Thermosetting polymers form highly cross-linked structures and cannot be softened or reused after setting. Therefore statement (1) is incorrect and is the correct answer.

Explanation

For reaction feasibility, E°cell must be positive. In option (A): E°cell = 0.34 − 0.80 = −0.46 V Since E°cell is negative, the reaction is non-spontaneous and cannot occur. Hence option (A) is correct.

Explanation

The temporary systematic IUPAC name for element 119 is formed from digits 1-1-9: un + un + enn + ium = ununennium Hence option (B) is correct.

Explanation

According to Hardy–Schulze rule, greater charge on counter ions gives greater flocculating power. Statement I is correct: Al³⁺ > Ba²⁺ > Na⁺ For positive sols, flocculating power should be: PO₄³⁻ > SO₄²⁻ > Cl⁻ Thus Statement II is incorrect. Hence option (D) is correct.

Explanation

In diborane (B₂H₆), boron atoms are approximately sp³ hybridised, not sp². Diborane contains two 3-centre-2-electron bridge bonds and four normal B-H bonds. Hence option (A) is incorrect and is the correct answer.

Explanation

Grignard reagents react with CO₂ to form magnesium carboxylate: RMgX + CO₂ → RCOO⁻Mg⁺X Hydrolysis then gives carboxylic acid: RCOO⁻Mg⁺X → RCOOH Hence option (B) is correct.

Explanation

Moles of HCl: = 0.5 × 0.050 = 0.025 mol Required moles of CaCO₃: = 0.025/2 = 0.0125 mol Mass of pure CaCO₃: = 0.0125 × 100 = 1.25 g For 95% purity: Required mass = 1.25/0.95 ≈ 1.32 g Hence option (C) is correct.

Explanation

O₂⁻ contains one unpaired electron and is therefore paramagnetic, not diamagnetic. Hence option (A) is the incorrect statement.

Explanation

Assertion refers to Schottky defect where missing cations and anions maintain neutrality. Reason correctly describes Frenkel defect. Both are true, but Reason does not explain Assertion. Hence option (C) is correct.

Explanation

Cell potential: E°cell = E°(reduction) − E°(oxidation) = 1.510 − 1.223 = +0.287 V Since E°cell is positive, the reaction is spontaneous and MnO₄⁻ can liberate O₂ in acidic medium. Hence option (B) is correct.

Explanation

Matching: MgH₂ → Ionic (iv) GeH₄ → Electron precise (i) B₂H₆ → Electron deficient (ii) HF → Electron rich (iii) Hence: (a)-(iv), (b)-(i), (c)-(ii), (d)-(iii) Therefore option (B) is correct.

Explanation

Nitro group is electron withdrawing and increases acidity of nitrophenols compared to phenol, so Statement I is correct. Acid strength differs among o-, m-, and p-nitrophenol because resonance and inductive effects vary with position. Hence Statement II is incorrect. Therefore option (D) is correct.

Explanation

Matching: Antacids → Cimetidine (iii) Antihistamines → Seldane (iv) Analgesics → Morphine (ii) Antimicrobials → Salvarsan (i) Thus: (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i) Hence option (C) is correct.

Explanation

Enzymes are mostly proteins (some are RNA catalysts), not polysaccharides. Hence option (D) is the incorrect statement.

Explanation

Statement (1) is incorrect because $d_{xy}$, $d_{yz}$ and $d_{zx}$ have similar four-lobed shapes oriented between axes, whereas $d_{z^2}$ has a distinct shape with two lobes along the z-axis and a toroidal ring, unlike $d_{x^2-y^2}$. Thus, $d_{x^2-y^2}$ and $d_{z^2}$ are not similar in shape. Statements (2), (3), and (4) are correct.

Explanation

Enantiomers are non-superimposable mirror images, not superimposable. Therefore statement (4) is incorrect and is the correct answer.

Explanation

Compound (1) is cyclooctatetraene, which adopts a non-planar tub structure and does not satisfy aromaticity requirements. The others satisfy aromatic stabilization conditions. Hence compound (1) is not aromatic.

Explanation

For zero-order reactions, rate is independent of concentration, so plotting rate vs concentration gives a constant line. For first-order reactions, half-life is independent of concentration, giving constant t½ vs concentration. Hence option (D) is correct.

Explanation

Dalton's law states: pᵢ = χᵢp where p is total pressure. Expression pᵢ = χᵢpᵢ° corresponds to Raoult's law and is incorrect here. Hence option (A) is correct.

Explanation

Primary aliphatic amines form unstable diazonium salts, so Statement I is correct. Aromatic diazonium salts are stable only at low temperatures (273–278 K), not above 300 K. Hence Statement II is incorrect. Therefore option (D) is correct.

Explanation

In KO₂ (potassium superoxide), oxidation state of K is +1 and O₂⁻ has charge −1. Therefore oxidation number of K is not +4. Hence option (C) is incorrect.

Explanation

For [Ag(H₂O)₂]⁺, Ag oxidation state = +1 → diaquasilver(I). For [Ag(CN)₂]⁻, Ag oxidation state = +1 → dicyanidoargentate(I). Hence option (A) is correct.

Explanation

Using Henderson–Hasselbalch equation: pH = pKa + log([salt]/[acid]) = 4.57 + log(0.10/0.01) = 4.57 + 1 = 5.57 Hence option (B) is correct.

Explanation

Work done in a p–V diagram equals the area under the curve. The isothermal expansion curve in option (C) encloses maximum area and hence corresponds to maximum work done. Therefore option (C) is correct.

Explanation

Matching: Cyanohydrin → HCN (iv) Acetal → alcohol (iii) Schiff's base → RNH₂ (ii) Oxime → NH₂OH (i) Thus: (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i) Hence option (A) is correct.

Explanation

Chlorobenzene is prepared by electrophilic aromatic substitution: C₆H₆ + Cl₂ → C₆H₅Cl using anhydrous FeCl₃ catalyst. Hence option (B) is correct.

Explanation

Kjeldahl method is not applicable to compounds containing nitrogen in nitro, azo, or ring nitrogen forms. It is applicable to amines like aniline. Hence option (D) is correct.

Explanation

Aldehydes and ketones exhibit dipole-dipole interactions, giving higher boiling points than hydrocarbons. Alcohols have stronger intermolecular hydrogen bonding, hence higher boiling points than aldehydes and ketones. Therefore both statements are correct. Hence option (B) is correct.

Explanation

Actual boiling point order is: H₂S < H₂Se < H₂Te < H₂O because H₂O shows strong hydrogen bonding. Hence Statement I is incorrect. Statement II is generally correct for H₂S, H₂Se and H₂Te due to increasing molar mass. Therefore option (A) is correct.

Explanation

Molality: m = moles of solute / kg of solvent 1 = 0.5 / kg solvent Thus solvent = 0.5 kg = 500 g Hence option (C) is correct.

Explanation

Ozonolysis producing HCHO indicates terminal alkene: CH₂=CH−R → HCHO + RCHO For 2-methyl propanal as the second product, alkene must be: CH₂=CH−CH(CH₃)₂ which is 3-methylbut-1-ene. Hence option (B) is correct.

Explanation

For first-order reactions: k = (2.303/t) log([A]₀/[A]) = (2.303/5) log(0.1/0.001) = (2.303/5)(2) = 0.9212 min⁻¹ Hence option (C) is correct.

Explanation

Moles of O₂: n = 64/32 = 2 mol Using PV = nRT: P = (2 × 0.0831 × 300)/10 ≈ 4.99 bar ≈ 4.9 bar Hence option (A) is correct.

Explanation

Lucas reagent distinguishes alcohols based on reactivity: 3° alcohol > 2° alcohol > 1° alcohol Tertiary alcohols immediately produce turbidity, while primary alcohols react very slowly. Hence Statement I is correct and Statement II is incorrect. Therefore option (D) is correct.

Explanation

For: 3O₂ ⇌ 2O₃ Kc = [O₃]²/[O₂]³ 3×10⁻⁵⁹ = [O₃]²/(0.040)³ [O₃]² = 1.92×10⁻⁶³ [O₃] = 4.38×10⁻³² M Hence option (B) is correct.

Explanation

Matching: Haematite → Fe₂O₃ (iii) Magnetite → Fe₃O₄ (i) Calamine → ZnCO₃ (ii) Kaolinite → Al₂(OH)₄Si₂O₅ (iv) Hence option (C) is correct.

Explanation

Using: ρ = ZM/(a³Nₐ) For fcc, Z = 4 Substituting values: M ≈ 63.1 u Hence option (B) is correct.

Explanation

Longest chain has 6 carbons. Numbering from bromine end gives OH at carbon 3: 1-bromo-4-methyl-5-chlorohexan-3-ol Hence option (D) is correct.

Explanation

Ligand field strength: en > H₂O Greater ligand strength → larger crystal field splitting → greater absorbed energy. Thus: [Ni(en)₃]²⁺ > [Ni(H₂O)₂(en)₂]²⁺ > [Ni(H₂O)(en)]²⁺ Hence option (D) is correct.

Explanation

Acetone and 2-pentanone in dilute NaOH undergo self-aldol and crossed aldol condensation, followed by dehydration to give α,β-unsaturated ketones. Among the given structures, option (C) cannot arise from the possible aldol condensation pathways and therefore is not formed.

Explanation

Oxides of sulphur pollution is enhanced in the presence of particulate matter, ozone and hydrogen peroxide due to accelerated oxidation processes leading to acid formation. Hydrocarbons are not directly responsible. Therefore, the correct combination is (a), (b), (d). Hence option (C) is correct.

Explanation

Benzonitrile (C₆H₅CN) undergoes reduction with LiAlH₄ to form phenethylamine (C₆H₅CH₂CH₂NH₂). Primary aliphatic amines react with NaNO₂/HCl to form unstable diazonium salts, which hydrolyse immediately to alcohols. Reaction sequence: C₆H₅CN → C₆H₅CH₂CH₂NH₂ → C₆H₅CH₂CH₂OH Therefore, the final product is 2-phenylethanol, corresponding to option (A).

Explanation

Electrostatic precipitators remove fine particulate matter from industrial and thermal power plant exhaust gases using electrically charged plates.