NEET UG

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Which one of the following conditions will favour maximum formation of the product in the reaction,A_2(g) + B_2(g) ⇌ X_2(g) Δ_rH = -X kJ ? Answer: 1. Low temperature and high pressure Apply Le Chatelier's principle to A₂+B₂⇌ X₂ , which is exothermic and reduces the number of gas... Delta G and equilibrium, factors affecting equilibrium, Le Chatelier's principle 1 answer
The correction factor 'a' to the ideal gas equation corresponds to Answer: 4. forces of attraction between the gas molecules In the van der Waals equation (P+an²/V²)(V-nb)=nRT , the term a corrects the press... Dynamic equilibrium and physical equilibria, Henry's law 1 answer
Hydrocarbon (A) reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted to gaseous hydrocarbon containing less than four carbon atoms. (A) is Answer: 4. CH ₄ The alkyl bromide undergoes Wurtz coupling, mathrm2R-Br+2Na→ R-R+2NaBr . The product has twice the carbon count of R, and mu... Alkanes: conformations, halogenation mechanism 1 answer
The compound C_7H_8 undergoes the following reactions :C_7H_8 3\ Cl_2/Δ A Br_2/Fe B Zn/HCl CThe product 'C' is Answer: 1. m-bromotoluene Work through the sequence: C₇H₈ is toluene. 3 Cl₂/Δ : side-chain chlorination gives benzotrichloride, C₆H₅CCl₃ (A)... Directive influence in monosubstituted benzene 1 answer
Identify the major products P, Q and R in the following sequence of reactions :benzene + CH_3CH_2CH_2Cl Anhydrous AlCl_3 P ; P [(ii) H_3O^+/Δ](i) O_2 Q + R Answer: 4. P = cumene (C ₆ H ₅ CH(CH ₃ ) ₂ ), Q = phenol (C ₆ H ₅ OH), R = CH ₃ - CO - CH ₃ Friedel-Crafts alkylation with n-propyl chloride... Electrophilic substitution: halogenation, nitration, Friedel-Crafts 1 answer
The compound A on treatment with Na gives B, and with PCl_5 gives C. B and C react together to give diethyl ether. A, B and C are in the order Answer: 4. C ₂ H ₅ OH, C ₂ H ₅ ONa, C ₂ H ₅ Cl A is ethanol. C₂H₅OH+Na→ C₂H₅ONa (B), and C₂H₅OH+PCl₅→ C₂H₅Cl (C). B and C then react by Will... Alcohols: identification of 1/2/3 alcohols, dehydration mechanism 1 answer
Which oxide of nitrogen is not a common pollutant introduced into the atmosphere both due to natural and human activity ? Answer: 1. N ₂ O ₅ N₂O , NO and NO₂ are all released by natural processes (soil bacteria, lightning) and by human activity (fuel combustion,... General trends, Group 15 and 16 1 answer
For the redox reactionMnO_4^- + C_2O_4^2- + H^+ Mn^2+ + CO_2 + H_2Othe correct coefficients of the reactants for the balanced equation are(columns: MnO_4^-, C_2O_4^2-, H^+) Answer: 3. 2, 5, 16 Balance by the ion-electron method. Reduction: mathrmMnO₄^-+8H^++5e^-→ Mn²⁺+4H₂O . Oxidation: mathrmC₂O₄²⁻→2CO₂+2e^- . M... Balancing redox reactions 1 answer
Consider the change in oxidation state of Bromine corresponding to different emf values as shown in the diagram below :BrO_4^- 1.82\ V BrO_3^- 1.5\ V HBrO 1.595\ V Br_2 1.0652\ V Br^-Then the species undergoing disproportionation is Answer: 4. HBrO A species disproportionates if the emf for its reduction (to the species on one side) is higher than the emf for its oxidati... EMF, Nernst equation and applications 1 answer
In which case is the number of molecules of water maximum ? Answer: 1. 18 mL of water Compare the number of moles; more moles means more molecules. 18 mL water = 18 g (density 1 g/mL) = 1 mol. 0.00224... Atomic and molecular masses, mole concept, molar mass 1 answer
Which of the following carbocations is expected to be most stable ? Answer: 2. cyclohexadienyl cation with NO ₂ at top carbon, H and Y on the sp ³ carbon, positive charge adjacent (picture) In the intermediat... Bond fission, free radicals, carbocations, carbanions and their stability 1 answer
Which of the following is correct with respect to -I effect of the substituents ? (R = alkyl) Answer: 3. - NR ₂ < - OR < - F The -I effect increases with the electronegativity of the atom attached to the carbon chain: N < O < F. Since... Inductive effect, electromeric effect, resonance, hyperconjugation 1 answer
Regarding cross-linked or network polymers, which of the following statements is incorrect ? Answer: 4. They contain strong covalent bonds in their polymer chains. Cross-linked (network) polymers are formed from bi- and tri-functiona... Amino acids, peptide bond, protein structure, denaturation 1 answer
The difference between amylose and amylopectin is Answer: 1. Amylopectin have 1 → 4 α -linkage and 1 → 6 α -linkage Both amylose and amylopectin are polymers of α -D-glucose, and they differ... Carbohydrates: classification, glucose, fructose 1 answer
In the structure of ClF_3, the number of lone pairs of electrons on central atom 'Cl' is Answer: 3. two Count electron pairs on Cl in ClF₃ : Cl has 7 valence electrons, 3 are used for bonds with F, leaving 4 electrons = 2 lone pa... VSEPR theory and shapes of molecules 1 answer
Considering Ellingham diagram, which of the following metals can be used to reduce alumina ? Answer: 2. Mg In an Ellingham diagram, a metal can reduce an oxide only if its own oxide-formation line lies below that of the oxide to be r... Gibbs energy change and equilibrium constant 1 answer
The correct order of atomic radii in group 13 elements is Answer: 4. B < Ga < Al < In < Tl Atomic radius generally increases down a group, but Ga is smaller than Al. Gallium follows the d-block (3d)... Atomic and ionic radii 1 answer
Which of the following oxides is most acidic in nature ? Answer: 3. BeO Acidic character of oxides falls as the metallic character of the element rises. In group 2, MgO, CaO and BaO are basic (basi... Valence, oxidation states and chemical reactivity 1 answer
Given van der Waals constant for NH_3, H_2, O_2 and CO_2 are respectively 4.17, 0.244, 1.36 and 3.59, which one of the following gases is most easily liquefied ? Answer: 1. NH ₃ The more easily a gas liquefies, the stronger its intermolecular attraction, and the van der Waals constant a measures exact... Dynamic equilibrium and physical equilibria, Henry's law 1 answer
Following solutions were prepared by mixing different volumes of NaOH and HCl of different concentrations :a. 60 mL M/10 HCl + 40 mL M/10 NaOHb. 55 mL M/10 HCl + 45 mL M/10 NaOHc. 75 mL M/5 HCl + 25 mL M/5 NaOHd. 100 mL M/10 HCl + 100 mL M/10 NaOHpH… Answer: 4. c pH = 1 means [H^+]=0.1 M, so excess strong acid of that concentration must remain after mixing. a: HCl 6 mmol, NaOH 4 mmol, exc... Ionization constants, ionization of water, pH scale 1 answer
The solubility of BaSO_4 in water is 2.42×10^-3 gL^-1 at 298 K. The value of its solubility product (K_sp) will be(Given molar mass of BaSO_4 = 233 g mol^-1) Answer: 1. 1.08×10⁻¹⁰ mol ² L ⁻² Convert solubility to mol/L, then use K_sp=s² for a 1:1 salt. s=dfrac2.42×10⁻³233=1.04×10⁻⁵\ mathrmmol L⁻¹... Solubility product 1 answer
Nitration of aniline in strong acidic medium also gives m-nitroaniline because Answer: 4. In acidic (strong) medium aniline is present as anilinium ion. Aniline is nitrated with a mixture of HNO₃ and H₂SO₄ , which is st... Directive influence in monosubstituted benzene 1 answer
Compound A, C_8H_10O, is found to react with NaOI (produced by reacting Y with NaOH) and yields a yellow precipitate with characteristic smell.A and Y are respectively Answer: 2. 1-phenylethanol (C ₆ H ₅ -CH(OH)-CH ₃ ) and I ₂ A positive iodoform test (yellow precipitate with characteristic smell) needs a C... Alpha-hydrogen acidity, aldol, Cannizzaro, haloform 1 answer
A mixture of 2.3 g formic acid and 4.5 g oxalic acid is treated with conc. H_2SO_4. The evolved gaseous mixture is passed through KOH pellets. Weight (in g) of the remaining product at STP will be Answer: 2. 2.8 Conc. H₂SO₄ dehydrates both acids. KOH absorbs CO₂ , so only CO remains. HCOOH→ CO+H₂O : 2.3 g / 46 = 0.05 mol, gives 0.05 mo... Carboxylic acids: acidic strength 1 answer

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