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NEET UGC Physics Question Paper for 2023

Physics Solve  Questions Paper 2023

With one of the highest numbers of candidates registered for the NEET 2024 exam, the NEET exam previous year question paper 2024 serves as an essential reference for the medical entrance exams’ current competitive nature.

SECTION-A

Question 1

A logic circuit provides the output Y as per the following truth table:

 
 
ABY
001
010
101
110

Answer: c) \bar{B}

Explanation:

  • Observe the truth table: Y = 1 when B = 0, and Y = 0 when B = 1

  • The output is independent of the value of A

  • Therefore, Y = \bar{B} (NOT B)


Question 2

A wheel is rolling on a level road. If its linear speed is v, which point moves faster – P (highest point) or Q (lowest point)?

Answer: b) Point P moves faster than point Q

Explanation:

  • In pure rolling motion:

    • The topmost point (P) has velocity = 2v (v + v)

    • The lowest point (Q) has velocity = 0 (v – v)

  • Therefore, point P moves faster than point Q


Question 3

Equivalent capacitance between terminal A and B:

Answer: 2μF

Explanation:

  • The given circuit is balanced (Wheatstone bridge configuration)

  • Redraw the circuit to simplify

  • The equivalent capacitance is calculated as:

    • Two parallel branches each with two capacitors in series

    • C_AB = (1/2 + 1/2)⁻¹ + (1/2 + 1/2)⁻¹ = 2μF


Question 4

Instantaneous power when displacement x = 2t – 1 and force = 5N:

Answer: a) 10 W

Explanation:

  • x = 2t – 1

  • Velocity, v = dx/dt = 2 m/s

  • Power, P = F × v = 5 × 2 = 10 W


Question 5

Assertion and Reason about electric dipole potential:

Answer: c) A is true but R is false

Explanation:

  • Potential at axial point of dipole: V = KP cosθ/r²

  • At θ = 0°: V = KP/r² = 9×10⁹ × 4×10⁻⁶ / 4 = 9×10³ V

  • At θ = 180°: V = -9×10³ V

  • Assertion A is true: V = ±9×10³ V

  • Reason R is false: The formula should be V = KP/r², not 2P/(4πε₀r²)


Question 6

Ratio V₁:V₂ for completely inelastic collision:

Answer: b) 2:1

Explanation:

  • Before collision: Body A (mass m) moving with velocity V₁, Body B at rest

  • After completely inelastic collision: Both move together with velocity V₂

  • Conservation of linear momentum:

    • m × V₁ + 0 = (m + m) × V₂

    • V₁ = 2V₂

    • V₁:V₂ = 2:1


Question 7

Magnetic moment of needle from oscillation:

Answer: d) 1280π²

Explanation:

  • Time period, T = 2π√(I/MB)

  • Given: T = 5/20 = 0.25 s, I = 9.8×10⁻⁶ kgm², B = 0.049 T

  • M = (2π/T)² × I/B

  • M = (4π² × 16 × 9.8×10⁻⁶) / 0.049

  • M = 1280π² × 10⁻⁵ Am²


Question 8

Unpolarised light at Brewster’s angle:

Answer: d) The reflected light will be completely polarised but the refracted light will be partially polarised

Explanation:

  • At Brewster’s angle, reflected ray is completely polarised

  • The refracted ray is partially polarised

  • This is a fundamental property of Brewster’s law


Question 9

Statements about solar cell and reverse biased pn junction:

Answer: a) A is correct but B is incorrect

Explanation:

  • Statement A is correct: Solar cell I-V characteristics lie in the IV quadrant

  • Statement B is incorrect: In reverse biased pn junction, current is due to minority charge carriers, not majority


Question 10

Graph of (1/λ²) vs kinetic energy E:

Answer: d)

Explanation:

  • De Broglie wavelength: λ = h/p = h/√(2mE)

  • 1/λ² = (2m/h²)E

  • This is a linear relationship: 1/λ² ∝ E

  • The graph is a straight line passing through origin


Question 11

Terminal voltage of battery with emf 10V and internal resistance 1Ω connected to external 4Ω:

Answer: c) 8V

Explanation:

  • Current, I = E/(R+r) = 10/(4+1) = 2A

  • Terminal voltage, V = E – Ir = 10 – 2(1) = 8V


Question 12

Quantities with same dimensions as solid angle:

Answer: a) strain and angle

Explanation:

  • Solid angle is a dimensionless quantity

  • Strain (change in length/original length) is dimensionless

  • Angle (arc/radius) is dimensionless

  • Stress has dimensions of pressure (ML⁻¹T⁻²)


Question 13

This appears to be missing/incomplete in the PDF


Question 14

This appears to be missing/incomplete in the PDF


Question 15

SHM: x = 5 sin(πt + π/3) m

Answer: b) 5m, 2s

Explanation:

  • Amplitude = 5m

  • ω = π = 2π/T

  • T = 2π/π = 2s


Question 16

Acceleration due to gravity on planet with mass 1/10 Earth and radius 1/2 Earth:

Answer: d) 3.92 m/s²

Explanation:

  • g’ = GM’/R’² = G(M/10)/(R/2)²

  • = G(M/10)/(R²/4) = 4GM/(10R²)

  • = 0.4 × g_Earth = 0.4 × 9.8 = 3.92 m/s²


Question 17

Force exerted by block A on block B (masses 2kg and 3kg, force 10N):

Answer: c) 6N

Explanation:

  • a = F/(m₁+m₂) = 10/(2+3) = 2 m/s²

  • Force on B = m₂a = 3 × 2 = 6N


Question 18

Work done along path bc in thermodynamic cycle:

Answer: Zero

Explanation:

  • Path bc is an isochoric process (constant volume)

  • Work done in isochoric process = 0 (W = PΔV, ΔV = 0)


Question 19

Statements about atoms:

Answer: c) Statement I is correct but Statement II is incorrect

Explanation:

  • Statement I is correct: Atoms are electrically neutral (equal protons and electrons)

  • Statement II is incorrect: Atoms are NOT all stable; many are radioactive and emit characteristic spectra only when excited


Question 20

Nuclear emission sequence:

Answer: 286, 81

Explanation:

  • ²⁹⁰₈₂X → α → ²⁸⁶₈₀Y (α decay: A-4, Z-2)

  • ²⁸⁶₈₀Y → e⁺ → ²⁸⁶₇₉Z (β⁺ decay: Z-1)

  • ²⁸⁶₇₉Z → β⁻ → ²⁸⁶₈₀P (β⁻ decay: Z+1)

  • ²⁸⁶₈₀P → e⁻ → ²⁸⁶₈₁Q (electron capture: Z+1)


Question 21

Particle moving with uniform speed in circular path:

Answer: d) Varying velocity and varying acceleration

Explanation:

  • Speed is constant but direction changes continuously

  • Velocity changes due to change in direction

  • Acceleration changes direction continuously (centripetal acceleration)


Question 22

Refractive index of prism:

Answer: b) √5/2

Explanation:

  • Apply Snell’s law at incidence surface:

    • 1 × sin30° = μ × sin(90° – c)

    • 1/2 = μ × cos c

    • sin c = 1/μ, cos c = √(μ²-1)/μ

    • 1/2 = μ × √(μ²-1)/μ = √(μ²-1)

    • Squaring: 1/4 = μ² – 1

    • μ² = 5/4

    • μ = √5/2


Question 23

Vernier constant:

Answer: b) 1/{100(N+1)}

Explanation:

  • Given: (N+1) VSD = N MSD

  • VSD = N/(N+1) MSD

  • V.C = MSD – VSD = MSD/(N+1)

  • 1 MSD = 0.1 mm = 0.01 cm

  • V.C = 0.01/(N+1) = 1/{100(N+1)} cm


Question 24

Young’s double slit with white light:

Answer: Coloured fringes will be observed

Explanation:

  • White light produces coloured interference fringes

  • Central fringe is white, surrounded by coloured fringes

  • Different wavelengths have different fringe widths

  • Pattern does not disappear


Question 25

Statements about photon:

Answer: b) A, B, C and D only

Explanation:

  • A: Energy of photon = hν ✓

  • B: Velocity of photon = c ✓

  • C: Momentum p = hν/c ✓

  • D: Both energy and momentum conserved in photon-electron collision ✓

  • E: Photon does NOT possess positive charge ✗ (photon is neutral)


Question 26

Output of logic gate:

Answer: d) AND gate

Explanation:

  • The given combination of gates is equivalent to an AND gate

  • This can be verified using De Morgan’s laws


Question 27

Match spectral lines of hydrogen:

 
 
TransitionWavelength (nm)
n₂=3 to n₁=2656.3
n₂=4 to n₁=2486.1
n₂=5 to n₁=2434.1
n₂=6 to n₁=2410.2

Answer: b) A-III, B-IV, C-II, D-I


Question 28

Excess force to lift disc from water:

Answer: a) 19.8 mN

Explanation:

  • Excess force = T × 2πR

  • = 0.07 × 2 × 3.14 × 0.045

  • = 197.82 × 10⁻⁴ N

  • = 19.8 × 10⁻³ N

  • = 19.8 mN


Question 29

Ideal transformer turns ratio:

Answer: b) 2:1

Explanation:

  • Np/Ns = 1/2

  • Vs/Vp = Ns/Np = 2:1

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Question 30

Maximum elongation of steel wire:

Answer: a) 4mm

Explanation:

  • δ_max = σ_elastic × L / Y

  • = (8×10⁸ × 1) / (2×10¹¹)

  • = 4×10⁻³ m

  • = 4 mm


Question 31

Potential difference between points C and P of charged spherical shell:

Answer: d) Zero

Explanation:

  • For a uniformly charged spherical shell:

    • Potential is constant inside and on the surface

    • V = kq/R for r ≤ R

    • Therefore, Vc = Vp

    • Vc – Vp = 0


Question 32

Resistance of combination:

Answer: b) 52 ohm

Explanation:

  • Wire of 100Ω divided into 10 equal parts: each part = 10Ω

  • First 5 parts in series: R₁ = 5 × 10 = 50Ω

  • Next 5 parts in parallel: R₂ = 10/5 = 2Ω

  • Series combination: R = 50 + 2 = 52Ω


Question 33

Magnetic field at centre of coil:

Answer: c) 4.4 mT

Explanation:

  • B = μ₀IN/(2R)

  • = (4π×10⁻⁷ × 7 × 100) / (2 × 0.1)

  • = 4.4 × 10⁻³ T

  • = 4.4 mT


Question 34

Match materials with susceptibility:

 
 
MaterialSusceptibility (χ)
Diamagnetic0 > χ ≥ -1
Ferromagneticχ >> 1
Paramagnetic0 < χ < ε
Non-magneticχ = 0

Answer: a) A-II, B-III, C-IV, D-I


Question 35

Tension in string when speed doubles:

Answer: b) 4T

Explanation:

  • Tension provides centripetal force: T = mω²r

  • If ω becomes 2ω, T’ = m(2ω)²r = 4mω²r = 4T


SECTION-B

Question 36

Current in capacitor circuit:

Answer: b) Displacement current of magnitude equal to I flows in the same direction as I

Explanation:

  • In the gap between capacitor plates, there is no conduction current

  • But displacement current exists: I_d = ε₀(dφ_E/dt)

  • I_d equals the conduction current I in magnitude

  • Flows in the same direction as I


Question 37

Peak current in capacitor circuit:

Answer: b) 0.93 A

Explanation:

  • C = 10μF = 10×10⁻⁶F

  • V_rms = 210V, f = 50Hz

  • Xc = 1/(2πfC) = 1/(2×3.14×50×10×10⁻⁶)

  • I_rms = V_rms/Xc

  • I_peak = I_rms × √2 ≈ 0.93A


Question 38

New time period of pendulum:

Answer: b) √2

Explanation:

  • T = 2π√(L/g)

  • Mass does not affect time period

  • New length = L/2

  • T’ = 2π√(L/2g) = (1/√2) × 2π√(L/g) = T/√2

  • Given T’ = x/2 × T

  • x/2 = 1/√2

  • x = √2


Question 39

T-V curves for ideal gas:

Answer: d) P₁ > P₂ > P₃

Explanation:

  • At same temperature, higher volume corresponds to lower pressure

  • From graph: V₃ > V₂ > V₁

  • Therefore: P₁ > P₂ > P₃


Question 40

Minimum energy to launch satellite at altitude 2R:

Answer: a) 5GmM/6R

Explanation:

  • Energy required = E_final – E_initial

  • E_initial = -GMm/R (on surface)

  • E_final = -GMm/(3R) (at radius 3R)

  • ΔE = -GMm/3R – (-GMm/R) = GMm/R – GMm/3R = 2GMm/3R

  • But for circular orbit, total energy = -GMm/(2r) where r = 3R

  • E_orbit = -GMm/(2×3R) = -GMm/6R

  • Energy required = (-GMm/6R) – (-GMm/R) = 5GMm/6R


Question 41

Property NOT of electromagnetic wave:

Answer: d) They originate from charges moving with uniform speed

Explanation:

  • EM waves originate from accelerating charges, not uniform motion

  • They are transverse ✓

  • Energy densities in E and B fields are equal ✓

  • Speed = 1/√(μ₀ε₀) ✓


Question 42

Circuit for bridge balance:

Answer: a)

Explanation:

  • Bridge balance condition: R₁/R₂ = R₃/R₄

  • In option a): 10/15 = 10/(5+RD)

  • This condition can be satisfied with appropriate RD


Question 43

Dimensionless factor:

Answer: b) αt/β

Explanation:

  • F = αt² + βt

  • By principle of homogeneity: [αt²] = [F] and [βt] = [F]

  • [α] = [F]/[t²] and [β] = [F]/[t]

  • [αt]/[β] = ([F]/[t²] × [t])/([F]/[t]) = [F]/[t] × [t]/[F] = dimensionless


Question 44

Ratio of power outputs in series and parallel:

Answer: b) 2:9

Explanation:

  • Heater A: 1kW, Heater B: 2kW

  • R_A = V²/P_A = V²/1, R_B = V²/P_B = V²/2

  • In series: P_series = V²/(R_A+R_B) = V²/(V² + V²/2) = 2/3 × V²/P_A? Let’s calculate properly:

    • P_series = V²/(R_A+R_B) = V²/(V² + V²/2) = 2/3 × V²/V² = 2/3 W

    • P_parallel = V²/R_A + V²/R_B = 1 + 2 = 3 W

    • P_series:P_parallel = 2:9


Question 45

Magnetic moment of bent iron bar:

Answer: b) M/2

Explanation:

  • Original magnetic moment: M = m × L (pole strength × length)

  • After bending at 60°, each half has length L/2

  • Magnetic moment = m × (L/2 + L/2 × cos60°) = m × L/2 × (1+1/2)? Actually:

    • Distance between poles = 2 × (L/2) × cos(30°) = L × cos30°

    • M_new = m × L × cos30° = M × cos30° = M × √3/2

    • Wait, let’s reconsider: For a bar bent at middle at 60°:

    • The magnetic moment = m × (L/2 + L/2 × cos60°) = m × L/2 × (1+1/2) = 3mL/4 = 3M/4

    • But the correct answer is M/2


Question 46

Compressive force developed in heated metallic bar:

Answer: b) 50 × 10³ N

Explanation:

  • Thermal strain = αΔT = 10⁻⁵ × 100 = 10⁻³

  • Thermal stress = Y × strain = 0.5×10¹¹ × 10⁻³ = 5×10⁷ N/m²

  • Force = stress × area = 5×10⁷ × 10⁻³ = 5×10⁴ = 50×10³ N


Question 47

v-t graph of motion:

Answer: (This appears incomplete in the PDF)


Question 48

Parallel plate capacitor plates moved closer:

Answer: b) A, C and E only

Explanation:

  • When plates are moved closer (d decreases):

    • A is correct: Charge increases (Q = CV, V constant)

    • B is incorrect: Energy increases (U = ½CV², C increases)

    • C is correct: Capacitance increases (C = ε₀A/d)

    • D is incorrect: Q/V = C increases (not constant)

    • E is correct: Q×V increases (Q increases, V constant)


Question 49

Magnifying power of telescope:

Answer: b) 28

Explanation:

  • For distant object: m = f₀/fₑ

  • = 140/5 = 28


Question 50

Force needed for sheet near magnetic pole:

Answer: b) A and C only

Explanation:

  • A is correct: Magnetic sheet experiences force from magnet

  • B is incorrect: Non-magnetic sheet experiences no force

  • C is correct: Conducting sheet moving through magnetic field experiences eddy currents (opposes motion)

  • D is incorrect: Non-conducting, non-polar sheet experiences no force


CHEMISTRY QUESTIONS (Pages 27-49)

Question 51

Arrange elements in increasing electronegativity: N, O, F, C, Si

Answer: (1) Si < C < N < O < F

Explanation:

  • Electronegativity increases across a period (left to right)

  • Electronegativity decreases down a group

  • Order: Si (Group 14, Period 3) < C (Group 14, Period 2) < N < O < F


Question 52

Identify reagents for transformation:

Answer: (2) (i) BH₃ (ii) H₂O₂/OH⁻ (iii) PCC

Explanation:

  • BH₃ + H₂O₂/OH⁻ = Hydroboration-oxidation (anti-Markovnikov addition)

  • PCC = Mild oxidizing agent (converts primary alcohol to aldehyde)


Question 53

Compound with fastest Sₙ1 reaction:

Answer: (4)

Explanation:

  • Sₙ1 reaction rate depends on carbocation stability

  • More stable carbocation → faster Sₙ1 reaction

  • Stability order: 3° > 2° > 1° > methyl


Question 54

Reaction quotient analysis:

Answer: (3) Reaction has tendency to go backward

Explanation:

  • Qc = [B][C]/[A]² = (2×10⁻³)²/(2×10⁻³)² = 1

  • Kc = 4×10⁻³

  • Qc > Kc → Reaction proceeds backward


Question 55

Highest number of helium atoms:

Answer: (1) 4 mol of helium

Explanation:

  • 4 mol = 4NA atoms

  • 4u = 1 atom

  • 4g = 1 mol = NA atoms

  • 2.271 L at STP = 0.1 mol = 0.1NA atoms


Question 56

Match thermodynamic processes:

Answer: (4) A-II, B-III, C-IV, D-I

 
 
ProcessCondition
IsothermalConstant temperature
IsochoricConstant volume
IsobaricConstant pressure
AdiabaticNo heat exchange

Question 57

Energy of electron in Be³⁺:

Answer: (1) -x

Explanation:

  • For He⁺: E₁ = -4R_H = -x → R_H = x/4

  • For Be³⁺ (n=2): E₂ = -R_H(4²/2²) = -4R_H = -x


Question 58

Match molecules with carbon-carbon bonds:

Answer: (3) A-III, B-IV, C-II, D-I

 
 
MoleculeBonds
EthaneOne σ-bond
EtheneOne σ, one π
C₂Two π-bonds
EthyneOne σ, two π

Question 59

Match compounds with shapes:

Answer: (1) A-I, B-IV, C-II, D-III

 
 
CompoundShape
NH₃Trigonal Pyramidal
BrF₅Square Pyramidal
XeF₄Square Planar
SF₆Octahedral

Question 60

E° value for Mn³⁺/Mn²⁺:

Answer: (3) d⁴ to d⁵ configuration

Explanation:

  • Mn³⁺: [Ar]3d⁴, Mn²⁺: [Ar]3d⁵

  • d⁵ is half-filled (extra stable)

  • Change from d⁴ to d⁵ provides extra stability

 

Section

Number of Questions

Marks for Correct Answer

Negative Marking

Total Marks

Physics

45

+4

−1

180

Chemistry

45

+4

−1

180

Biology (Botany + Zoology)

90

+4

−1

360

Total

180

  

720

Question 61

Kp and Kc not equal:

Answer: (1) PCl₅(g) ⇌ PCl₃(g) + Cl₂(g)

Explanation:

  • Kp = Kc(RT)^Δn_g

  • For PCl₅: Δn_g = 2-1 = 1 ≠ 0

  • For others: Δn_g = 0


Question 62

Group 16 element not showing -2 oxidation state:

Answer: (4) Po

Explanation:

  • Polonium shows only +2 and +4 oxidation states

  • Other elements show -2, +2, +4, +6


Question 63

Same spin-only magnetic moment:

Answer: (1) B and D only

Explanation:

  • Spin-only moment = √(n(n+2)) BM

  • Cr²⁺: n=4, Fe²⁺: n=4 → Same moment

  • Ti³⁺: n=1, Mn²⁺: n=5, Sc³⁺: n=0


Question 64

Compound with two tertiary carbons:

Answer: (3) 2,3-dimethylbutane

Explanation:

  • Structure: CH₃-CH(CH₃)-CH(CH₃)-CH₃

  • Both middle carbons are tertiary

  • Other options have 0 or 1 tertiary carbons


Question 65

Boiling point of isomeric pentanes:

Answer: (1) Both statements correct

Explanation:

  • n-pentane > isopentane > neopentane

  • Branching → spherical shape → less surface area → weaker IMF → lower BP


Question 66-70

These questions are present in the Biology section of the PDF


Question 71

Most stable carbocation:

Answer: (4)

Explanation:

  • Stability depends on hyperconjugation extent

  • More hyperconjugative structures → more stability

  • Order: (4) > (2) > (1) > (3)


Question 72

Purification technique for sublimation:

Answer: (2) Sublimation

Explanation:

  • Sublimation: Solid → Vapour (without liquid state)

  • Used for substances like iodine, camphor, NH₄Cl


Question 73

Match complexes with isomerism:

Answer: (1) A-II, B-III, C-IV, D-I

 
 
ComplexIsomerism
[Co(NH₃)₅(NO₂)]Cl₂Linkage
[Co(NH₃)₅(SO₄)]BrIonization
[Co(NH₃)₆][Cr(CN)₆]Coordination
[Co(H₂O)₆]Cl₃Solvate

Question 74

Glucose does not react with:

Answer: (3) B and E

Explanation:

  • Glucose does NOT give Schiff’s test (B)

  • Glucose does NOT form bisulphite addition product (E)

  • Despite having aldehyde group, cyclic hemiacetal structure prevents these reactions


Question 75

Match reactions:

Answer: (3) A-IV, B-I, C-II, D-III


Question 76

Activation energy calculation:

Answer: (4) rate constant at two different temperatures

Explanation:

  • Arrhenius equation: log(k₂/k₁) = (Ea/2.303R)(1/T₁ – 1/T₂)


Question 77

Match conversions with Faraday:

Answer: (1) A-II, B-IV, C-I, D-II

 
 
ConversionFaraday
H₂O → O₂2F
MnO₄⁻ → Mn²⁺5F
1.5 mol Ca3F
FeO → Fe₂O₃1F

Question 78

Intramolecular hydrogen bonding:

Answer: (1)

Explanation:

  • Intramolecular H-bonding occurs in o-nitrophenol

  • Requires proper geometry (5- or 6-membered ring)


Question 79

Statements about aniline:

Answer: (1) Both statements true

Explanation:

  • Aniline does NOT undergo Friedel-Crafts (forms salt with AlCl₃)

  • Aniline cannot be prepared by Gabriel synthesis (aryl halides don’t undergo SN)


Question 80

Alcohol reacting instantaneously with Lucas reagent:

Answer: (4) Tertiary alcohol

Explanation:

  • Tertiary alcohols → immediate turbidity with Lucas reagent

  • Secondary → after 5-10 minutes

  • Primary → slowly or not at all


Question 81

Increasing order of first ionization enthalpy:

Answer: (2) Li < B < Be < C < N

Explanation:

  • General trend increases across period

  • Exception: Be (2s²) > B (2p¹) due to stability of full orbital


Question 82

Which reaction is NOT redox:

Answer: (4) BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl

Explanation:

  • No change in oxidation states

  • Double displacement/precipitation reaction


Question 83

Match quantum numbers:

Answer: (2) A-III, B-IV, C-I, D-II

 
 
Quantum NumberInformation
mOrientation of orbital
mₛOrientation of spin
lShape of orbital
nSize of orbital

Question 84

Processes where entropy increases:

Answer: (3) A, C and D

Explanation:

  • A: Liquid → Vapour (ΔS > 0)

  • B: Cooling from 130K to 0K (ΔS < 0)

  • C: More gas moles formed (ΔS > 0)

  • D: 1 mol → 2 mol (ΔS > 0)


Question 85

Mass of NaOH left unreacted:

Answer: (2) 250 mg

Explanation:

  • Moles HCl = 0.75 × 25/1000 = 0.01875 mol

  • Mass HCl = 0.01875 × 36.5 = 0.684 g

  • 36.5g HCl reacts with 40g NaOH

  • 0.684g HCl reacts with (40/36.5)×0.684 = 0.750g NaOH

  • NaOH left = 1 – 0.750 = 0.250g = 250mg


Question 86

Products A and B:

Answer: (4) H₃PO₃ and POCl₃

Explanation:

  • 3ROH + PCl₃ → 3RCl + H₃PO₃ (A)

  • ROH + PCl₅ → RCl + HCl + POCl₃ (B)


Question 87

This appears incomplete in the PDF


Question 88

Major product C:

Answer: (1) propylamine

Explanation:

  • Hofmann bromamide degradation: RCONH₂ → RNH₂

  • Converts amide to amine with one less carbon


Question 89

Acid added to Mohr’s salt:

Answer: (4) dilute sulphuric acid

Explanation:

  • Dilute H₂SO₄ prevents hydrolysis of Fe²⁺

  • HCl and HNO₃ can oxidize Fe²⁺


Question 90

Degree of dissociation of NO:

Answer: (4) 0.717

Explanation:

  • Kc = 1.607 from equilibrium concentrations

  • For 2NO(g) ⇌ N₂(g) + O₂(g)

  • Using ICE table: Kc = (0.05α)²/[0.1(1-α)]²

  • α/(1-α) = 2.54

  • α = 0.717


Question 91

Work done in reversible isothermal expansion:

Answer: (2) -413.14 calories

Explanation:

  • W = -2.303 nRT log(P₁/P₂)

  • = -2.303 × 1 × 2 × 298 × log(20/10)

  • = -2.303 × 1 × 2 × 298 × log 2

  • = -413.14 calories


Question 92

Mass of copper deposited:

Answer: (2) 0.315 g

Explanation:

  • Cu²⁺ + 2e⁻ → Cu

  • w = MIt/(nF)

  • = 63 × 9.6487 × 100/(2 × 96487)

  • = 0.315 g


Question 93

Activation energy:

Answer: (1) 38.04 kJ/mol

Explanation:

  • log(k₂/k₁) = (Ea/2.303R)(1/T₁ – 1/T₂)

  • log 4 = (Ea/2.303×8.314)(1/300 – 1/330)

  • Ea = 3.804×10⁴ J/mol = 38.04 kJ/mol


Question 94

Temperature from osmotic pressure:

Answer: (1) 37°C

Explanation:

  • π = CRT

  • Slope = RT

  • T = 25.73/0.083 = 310 K = 37°C


Question 95

Increasing group number of cations:

Answer: (1) B, A, D, C, E

Explanation:

  • Cu²⁺ (Group II) < Al³⁺ (Group III) < Co²⁺ (Group IV) < Ba²⁺ (Group V) < Mg²⁺ (Group VI)


Question 96

Homoleptic/heteroleptic complexes:

Answer: (1) Both statements true

Explanation:

  • [Co(NH₃)₆]³⁺: Only NH₃ ligands → Homoleptic

  • [Co(NH₃)₄Cl₂]⁺: Two types of ligands → Heteroleptic


Question 97

Diamagnetic lanthanoid ions:

Answer: (1) Ce⁴⁺ and Yb²⁺

Explanation:

  • Ce⁴⁺: f⁰ (0 unpaired) → Diamagnetic

  • Yb²⁺: f¹⁴ (0 unpaired) → Diamagnetic

  • All others have unpaired electrons → Paramagnetic


Question 98

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Question 99

Correct statement:

Answer: (4) Three canonical forms can be drawn for CO₃²⁻ ion

Explanation:

  • Ozone: 2 resonance structures (not 3)

  • BF₃: Zero dipole moment (symmetrical)

  • NH₃ dipole > NF

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