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Chapter — NEET UG Chemistry PYQs

376 previous year questions from Chapter with answers and solutions. Numbered list, year tags, and one-tap solutions — built for serious JEE / NEET practice.

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1

Which of the following postulates of Dalton's atomic theory provides the direct theoretical basis for the law of conservation of mass?

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Consider the following five samples of substances: A. 88 g of CO ₂ B. 96 g of O ₂ C. 34 g of NH ₃ D. 36 g of H ₂ O E. 40 g of Ne Which of the given samples contain an identical tot

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If the shortest wavelength of the Lyman series for a hydrogen atom is x , then the longest wavelength of the Paschen series for a He ⁺ ion is:

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What are the energy of the second Bohr orbit of Be ³⁺ and the radius of the third Bohr orbit of He ⁺ respectively? [Given: R _ H = 2.18 10⁻¹⁸ J , a ₀ = 52.9 pm ]

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Consider the following electronic configurations of neutral atoms: A. [ Ne ] 3s^2 3p^4 B. [ Ar ] 3d^6 4s^2 C. [ Kr ] 4d¹⁰ 5s^2 D. [ Xe ] 4f¹⁴ 5d¹⁰ 6s^2 6p^2 E. [ Ar ] 3d^5 4s^1 Whi

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Consider the following sequences of molecules and their associated properties: (I) CH ₃ Cl CH ₂ Cl ₂ CHCl ₃ : Dipole moment (II) H ₂ Te H ₂ S H ₂ O : Bond angle (III) CO CO ₂ CO ₃²

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The potential energy profile for a hypothetical reaction X Y is shown in the given figure. Based on the graph, what is the enthalpy change ( H ) for this reaction?

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For a reversible gas-phase reaction, X(g) + Y(g) Z(g) the rate constant for the forward reaction is 82 times the rate constant for the backward reaction at 500 K. The value of equi

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Consider the following equilibrium for the synthesis of sulfur trioxide: 2 SO ₂( g ) + O ₂( g ) 2 SO ₃( g ) H = -198 kJ mol ⁻¹ Which of the following conditions will favor the maxi

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Hydrogen sulfide ( H₂S ) is a weak diprotic acid that ionizes in two successive steps in an aqueous solution, with ionization constants K_ a₁ and K_ a₂ . If K_ eq represents the ov

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What are the respective oxidation states of the underlined atoms in O F₂ , Li H , and K₂ Cr ₂O₇ ?

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An analytical chemist needs to perform the following four separations: (I) Separation of a mixture of ether (b.p. 308 K ) and toluene (b.p. 384 K ) (II) Separation of two miscible

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Observe the given compounds I, II, and III. Identify the correct decreasing order of bond dissociation energy for the C-H bonds marked with an asterisk (*).

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The given flowchart illustrates various methods for the preparation of benzene. Identify the correct set of reagents A, B, and C required for these conversions.

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The skeletal structure of a cyclic hydrocarbon is shown in the figure above. Which of the following is the correct observation when this compound is shaken with aqueous bromine ( B

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Based on the physical states of the solute and the solvent, identify the incorrect match from the following examples of solutions:

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Assuming complete dissociation of the electrolytes, which of the following aqueous solutions will freeze at the lowest temperature?

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A binary solution is prepared by mixing 2 moles of liquid P and 3 moles of liquid Q. At a certain temperature, the vapour pressures of pure P and pure Q are 120 mm Hg and 160 mm Hg

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The molar conductivity of a 0.02 M solution of propanoic acid is 31.2 S cm ^2 mol ⁻¹ . What is the percentage dissociation of the acid in this solution? [Given: Limiting molar cond

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A chemical reaction has a rate constant of 6.93 10⁻³ ~s ⁻¹ . How much time will it take for the reaction to be 93.75 % complete? (Given : 2 = 0.301 )

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Identify the set of coordination complexes in which all the species are diamagnetic in nature.

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Arrange the following coordination complexes in the increasing order of the wavelength of light absorbed by them: A. [ Cr ( NH ₃ )₆ ]³⁺ B. [ Cr ( CN )₆ ]³⁻ C. [ Cr ( H ₂ O )₆ ]³⁺ D

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According to Werner's coordination theory, which of the following empirical formulations of platinum(IV) chloride with ammonia will exhibit the lowest molar conductance in aqueous

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Predict the major product 'Z' in the following sequence of reactions.

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Consider the three alkyl halides labelled as I, II, and III in the given figure. Which of the following represents the correct decreasing order of their reactivity towards an S _ N

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What is the total number of acyclic ether isomers (including both structural and stereoisomers) possible for the molecular formula C ₅ H ₁₂ O ?

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Identify the major organic product formed in the following reaction.

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Identify the appropriate reagent 'X' to carry out the given chemical transformation.

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Identify the correct decreasing order of acidic strength for the following substituted carboxylic acids.

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An organic compound X ( C ₆ H ₇ N ) on treatment with NaNO ₂ and dilute HCl at 273-278 K forms an intermediate Y . The intermediate Y is unstable in the dry state but can be mainta

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The cyclic structure of D-(-)-fructose is known as a furanose structure. According to its structural representation, the furanose ring of fructose consists of:

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Arrange the following samples of oxygen gas ( O₂ ) in increasing order of the number of molecules present in them: (I) 1.6 g of O₂ (II) 22.4 L of O₂ at STP (III) 0.08 mol of O₂ (IV

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1.12 g of solid potassium hydroxide (KOH) is added to 50 mL of a 0.25 M aqueous solution of H ₂ SO ₄ . Assuming complete neutralization, the mass of the unreacted reactant left in

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If the energy of an electron in the first Bohr orbit of a hydrogen atom is -E , then the energy of an electron in the third Bohr orbit of a He ⁺ ion is:

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Based on the quantum mechanical model of the atom, match the quantum numbers in List I with their allowed values in List II. List I List II A Principal quantum number ( n ) I -l to

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Observe the given structure of 1-buten-3-yne where specific bonds are labeled as 'a', 'b', 'c', and 'd'. Match the labeled bonds in List I with their corresponding nature in List I

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Observe the given bar graph comparing the boiling points of the three isomers of nitrophenol. The noticeably lower boiling point of o -nitrophenol compared to its m - and p -isomer

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Identify the processes in which the entropy of the system decreases. A. Freezing of water to ice at 273 K . B. 2 SO _ 2( g ) + O _ 2( g ) 2 SO _ 3( g ) C. Mixing of two non-reactin

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For the reaction CO(g) + H ₂ O(g) CO ₂ (g) + H ₂ (g) , the equilibrium constant K_c is 4.0 at a specific temperature. If a reaction mixture contains 0.1 M of CO , 0.1 M of H ₂ O ,

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For which of the following reversible reactions is the relationship K_p = K_c (RT)⁻¹ correct?

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Which of the following mixtures is most suitably separated by the technique of sublimation?

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A saturated acyclic hydrocarbon with the molecular formula C ₇ H ₁₆ is found to have exactly one tertiary carbon atom and one quaternary carbon atom. What is the IUPAC name of this

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Consider the organic molecule 2-methylbutane ( CH₃-CH(CH₃)-CH₂-CH₃ ). If a hydride ion ( H^- ) is removed from this molecule to generate a carbocation, removal from which carbon at

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At a constant temperature, the Henry's law constants ( K_H ) for four gases W, X, Y, and Z in water are 35 kbar , 0.15 kbar , 76 kbar , and 1.67 kbar respectively. The correct incr

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The given plot shows the variation of k versus 1 T for two different chemical reactions, Reaction 1 and Reaction 2. Based on the graph, which of the following relations is correct

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The third ionization enthalpy of manganese ( Z=25 ) is exceptionally high, whereas that of iron ( Z=26 ) is comparatively lower. This contrast is best explained by the respective e

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Which of the following ions possess a spin-only magnetic moment of approximately 2.83 BM ? A. V ³⁺ B. Co ²⁺ C. Ni ²⁺ D. Cu ⁺ E. Mn ³⁺ Choose the most appropriate answer from the op

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Observe the different pairs of isomeric coordination compounds described in List I. Match List I with the correct type of structural isomerism they represent in List II. List I Lis

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(I) (II) (III) Consider the three substituted benzyl chlorides. Which of the following represents the correct decreasing order of their reactivity towards S_ N 1 solvolysis?

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An organic compound whose structure is shown above is treated with Lucas reagent (a mixture of concentrated HCl and anhydrous ZnCl₂ ) at room temperature. Which of the following is

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To prepare Fehling's reagent for the identification of aliphatic aldehydes, aqueous copper sulphate is mixed with an alkaline solution of a complexing agent. This agent prevents th

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A chemical analysis of an inorganic compound shows that it contains 40 % of element P , 30 % of element Q , and 30 % of element R by mass. If the respective atomic masses of P, Q ,

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Calculate the work done when 5 moles of an ideal gas expand isothermally and reversibly from a volume of 2 L to 20 L at 27^ C . (Given R = 8.314 J K ⁻¹ mol ⁻¹ )

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The osmotic pressure of an aqueous solution of urea (molar mass = 60 g mol ⁻¹ ) is 0.492 atm at 300 K . Assuming the density of the solution to be 1.0 g mL ⁻¹ and using R = 0.082 L

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A current of 1.93 A is passed through an aqueous solution of silver nitrate ( AgNO ₃ ) for 500 seconds . What is the mass of silver deposited at the cathode? (Given: Molar mass of

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The rate constant of a decomposition reaction becomes ten times its initial value when the temperature is increased from 200 K to 250 K . Calculate the activation energy of the rea

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Identify the major products A and B formed in the following reaction sequence.

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Consider the following reaction: Identify the major organic products X and Y .

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Given below are certain basic radicals. Based on inorganic qualitative analysis, arrange them in increasing order of their group number. A. Zn ²⁺ B. Sr ²⁺ C. As ³⁺ D. NH₄ ⁺ E. Cr ³

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What is the mass of acetylene ( C₂H₂ ) gas produced when 32 g of a commercial sample of calcium carbide ( CaC₂ ), which is 75 % pure, reacts completely with an excess of water? (At

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The elements P , S , K , and Ca form stable ions to achieve the nearest noble gas configuration. Identify the smallest and the largest ions formed among them, respectively.

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Let x be the maximum number of electrons that can be accommodated in a particular subshell. Which of the following expressions correctly defines the azimuthal quantum number ( l )

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The stability of the lower oxidation state increases down a group in the p-block due to the inert pair effect. Based on this principle, which of the following oxides will act as th

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Identify the correct count of -bonds, -bonds, and lone pairs of electrons present in a molecule of aniline.

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Which of the following sets of molecules contains ONLY those species that violate the octet rule?

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A hypothetical reaction is observed to be non-spontaneous at low temperatures, but it becomes spontaneous when the temperature is raised significantly. Which of the following condi

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Which of the following pairs of chemical species consists entirely of Lewis acids?

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Identify the correct classification for the organic halogen compound shown:

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Identify the major product (P) formed in the given reaction.

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The reaction, CF₃CH₂OH + CH₃CH₂ONa CF₃CH₂ONa + CH₃CH₂OH suggests that:

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A conductivity cell filled with 0.1 M HCl solution has a resistance of 50 at 300 K . If the conductivity of 0.1 M HCl is 3.6 10⁻² S cm ⁻¹ , what will be the conductivity of a 0.02

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Assertion : p -Methoxyphenol is a weaker acid than m -methoxyphenol. Reason : The -OCH₃ group exerts a +I effect which destabilizes the conjugate base.

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In the lanthanoid series, the +3 oxidation state is the most characteristic and stable state in aqueous solutions, despite the large amount of energy required to remove three elect

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Consider the given reaction sequence and identify the final major product 'X'.

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An alcohol, whose structure is shown in the figure, is heated with concentrated hydroiodic acid (HI) to yield a major alkyl halide product via a substitution mechanism. What is the

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What is the mass (in grams) of the hydrocarbon formed when 0.5 moles of sodium adipate is heated strongly with an excess of soda lime?

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Consider the following chemical reactions: (I) Benzamide Br₂, NaOH Product A (II) Benzamide [ (ii) H₂O] (i) LiAlH₄ Product B (III) Phenyl isocyanide [ (ii) H₂O] (i) LiAlH₄ Product

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In Rutherford's scattering experiment, which specific observation led to the conclusion that the entire positive charge and most of the mass of the atom are densely concentrated in

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For which of the following gaseous reactions is the change in enthalpy ( H ) exactly equal to the change in internal energy ( U ) at a constant temperature?

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For the gas-phase reaction X₂(g) + Y₂(g) 2XY(g) , the equilibrium concentrations of X₂ , Y₂ , and XY at 500 K are 0.01 mol L ⁻¹ , 0.01 mol L ⁻¹ , and 0.1 mol L ⁻¹ respectively. Cal

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Consider the following redox reaction in an acidic medium: x MnO ₄⁻ + y C ₂ O ₄²⁻ + z H ⁺ x Mn ²⁺ + 2y CO ₂ + z 2 H ₂ O When the equation is correctly balanced using the smallest p

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Which among the following alcohols will undergo acid-catalyzed dehydration most rapidly?

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Consider the four cyclic species labeled (I) to (IV) in the given figure. According to Huckel's rule, which of the following combinations correctly identifies ONLY the aromatic spe

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Assertion (A): Oxygen molecule ( O₂ ) is paramagnetic in nature. Reason (R): The molecular orbital electronic configuration of O₂ contains two unpaired electrons in its bonding mol

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The thermodynamic stability of a coordination compound in aqueous solution is quantitatively expressed by its overall formation constant ( ). Among the given species, which complex

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Consider the chemical reaction shown in the given figure. Which of the following correctly identifies the major products P and Q?

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Identify the final major product [S] obtained in the following sequence of reactions: (i) LiAlH₄ , (ii) H₃O^+ [ P ] [ ] conc. H₂SO₄ [ Q ] (i) B₂H₆ /THF, (ii) H₂O₂/OH^- [ R ] PCC [

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An organic compound 'Y' has the structure shown in the figure. Compound 'Y' is treated with an alkaline solution of ammoniacal silver nitrate and heated. Which of the following rep

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Which of the following gas samples contains the same number of molecules as 3.4 g of ammonia ( NH ₃ )?

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The atomic radii of the elements Na , Mg , Al , and Si are given in a random order as 118 pm , 143 pm , 160 pm , and 186 pm . Based on the periodic trend, which of the following re

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Given below is an outline of the modern periodic table where four elements are marked as P, Q, R, and S. Match List I (the marked elements) with List II (their characteristic prope

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Consider a chemical reaction where the total enthalpy of the products is greater than the total enthalpy of the reactants. Which of the following statements are correct for this pr

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Consider the following two equilibrium reactions at a constant temperature: (i) CO(g) + 2H₂(g) CH₃OH(g) ; Equilibrium constant = K₁ (ii) 3CH₃OH(g) 3CO(g) + 6H₂(g) ; Equilibrium con

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The dissociation of phosphorus pentachloride is an endothermic process: PCl ₅( g ) PCl ₃( g ) + Cl ₂( g ), H > 0 According to Le Chatelier's principle, which of the following condi

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During the titration of ammonium hydroxide (taken in a conical flask) against dilute hydrochloric acid, which indicator is most suitable and what is the colour change observed at t

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Aniline (boiling point 184^ C ) is often purified from a crude mixture using steam distillation. Which of the following statements correctly describe the principles of this purific

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Identify the IUPAC name of the major product Y formed in the following reaction sequence.

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Calculate the mass of oxalic acid dihydrate needed to prepare 500 mL of a 0.02 M aqueous solution. (Molar mass of H₂C₂O₄ 2H₂O = 126 g mol ⁻¹ )

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An electrolyte concentration cell consists of two identical metallic electrodes dipped in solutions of the same electrolyte but at different concentrations. Which of the following

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The initial rate of a chemical reaction, P + Q Products , was measured at various initial concentrations of the reactants. The experimental data is provided in the accompanying tab

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The given figure displays the Arrhenius plots ( k vs 1 T ) for two distinct chemical reactions, labeled as Reaction X and Reaction Y. Based on the provided graph, identify the corr

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An aqueous solution of potassium dichromate is orange in colour. On adding an alkali to this solution, the colour changes to yellow. This colour change is due to the formation of:

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Unlike transition metal complexes, the colors of lanthanoid(III) complexes are generally not affected by the nature of the ligands. The primary reason for this behavior is that:

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The oxidation states shown by Mn in the given reaction are : 2 MnO ₄⁻ + 3 Mn ²⁺ + 2 H ₂ O 5 MnO ₂ + 4 H ⁺ A. +6 B. +4 C. +3 D. +7 E. +2 Choose the correct answer from the options g

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Which of the following ions or molecules acts as an ambidentate ligand in coordination compounds?

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Ethylenediaminetetraacetate ( EDTA ⁴⁻ ) is a widely used ligand in coordination chemistry. Which of the following correctly describes its denticity and the nature of its donor atom

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Identify the major product R formed in the following reaction sequence: C₆H₅CH₂COOH [ ] NH₃ P Br₂/KOH Q [ (ii) H₂O ] (i) NaNO₂ + HCl R

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Identify the major product 'Z' in the following sequence of reactions: C₆H₅-CH₂-CH₂-Br [ ] alc. KOH X HBr Y [ ] aq. KOH Z

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Consider the chemical reaction scheme shown in the given figure. Which of the following statements is correct regarding the major products Y and Z ?

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Which of the following amines will produce an intensely foul-smelling substance when heated with chloroform and ethanolic potassium hydroxide, but fails to form a stable diazonium

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The given figure shows the potential energy curves for four hydrogen halide molecules as a function of internuclear distance. Match the curves given in List I with the correspondin

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For the reaction 2 NO ( g ) + O ₂( g ) 2 NO ₂( g ) at 400 K , the change in internal energy ( U ) is -70 kJ . What will be the enthalpy change ( H ) for the reaction at the same te

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The solubility of AgSCN in pure water is x times its solubility in a 0.001 M KSCN solution. The value of x is: (Given : K_ sp of AgSCN = 10⁻¹² )

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During the elemental analysis of a newly synthesized drug molecule, 0.45 g of the sample was subjected to Liebig's combustion method. The experiment yielded 0.66 g of carbon dioxid

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The carbon-carbon single bond length in propene ( CH₃-CH=CH₂ ) is observed to be slightly shorter than the standard C-C single bond length in propane ( 154 pm ). Which electronic e

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Consider the skeletal structures of the four hydrocarbons shown below. Which of these hydrocarbons will be oxidized to the corresponding alcohol upon treatment with potassium perma

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A solution is prepared by dissolving W grams of a non-electrolyte polymer (molar mass = 6000 g mol ⁻¹ ) in enough water to make 500 mL of solution. This solution is found to be iso

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For the galvanic cell reaction given below: 2 Cr(s) + 3 Cd ²⁺ (aq) 2 Cr ³⁺ (aq) + 3 Cd(s) The standard cell potential ( E^ _ cell ) is 0.34 V . Calculate the standard Gibbs free en

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For a first-order decomposition reaction, the half-life period decreases from 40 minutes at 27^ C to 20 minutes at 37^ C . What is the activation energy of this reaction? (Given: 2

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The given reaction illustrates the direct iodination of ethylbenzene. Unlike chlorination or bromination, this reaction is reversible due to the formation of a strong reducing bypr

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