JEE Main 2026 — 28 Jan Shift 2 (3:00 PM - 6:00 PM) (Previous Year
JEE Main · 2026 · with answers and explanations
- questions
- 75
- Total marks
- 300
- Duration
- 180 minutes
- Negative marking
- −1
Subjects: Mathematics · Physics · Chemistry
Question 1
Mathematics · 4 marks · −1The sum of all the elements in the range of , , , where , is :
- A.0
- B.2
- C.-2
- D.4
Correct answer: B
Explanation: Quadrants give 4, , 0, : range , sum 2.
Question 2
Mathematics · 4 marks · −1Given below are two statements : Statement I : The function defined by is one-one. Statement II : The function defined by is many-one. In the light of the above statements, choose the correct answer from the options given below :
- A.Statement I is true but Statement II is false
- B.Both Statement I and Statement II are true
- C.Statement I is false but Statement II is true
- D.Both Statement I and Statement II are false
Correct answer: B
Question 3
Mathematics · 4 marks · −1Let and . Then the max is :
- A.8
- B.
- C.9
- D.
Correct answer: D
Explanation: B is an ellipse with ; farthest point from 2 is at distance ; max .
Question 4
Mathematics · 4 marks · −1Let the arithmetic mean of and be , . If is such that are in A.P., then the equation has :
- A.one root in (1, 4) and another in (-2, 0)
- B.complex roots of magnitude less than 2
- C.both roots in the interval (-2, 0)
- D.one root in (0, 2) and another in (-4, -2)
Correct answer: A
Explanation: With , , : ; forces , so , , . Equation : roots 2 and .
Question 5
Mathematics · 4 marks · −1is equal to :
- A.
- B.
- C.
- D.
Correct answer: D
Explanation: Terms after the first: ; adding gives .
Question 6
Mathematics · 4 marks · −1The sum of the coefficients of and in is :
- A.
- B.
- C.
- D.
Correct answer: B
Explanation: Coefficient of is ; .
Question 7
Mathematics · 4 marks · −1Given below are two statements : Statement I : is divisible by 7. Statement II : The integral part of is an odd number. In the light of the above statements, choose the correct answer from the options given below :
- A.Statement I is false but Statement II is true
- B.Statement I is true but Statement II is false
- C.Both Statement I and Statement II are false
- D.Both Statement I and Statement II are true
Correct answer: D
Explanation: I: , with odd powers. II: even integer and , so is odd.
Question 8
Mathematics · 4 marks · −1The probability distribution of a random variable X is given below : X: , , , , , , , with P(X): , , , , , , , . If , then is equal to :
- A.
- B.
- C.
- D.
Correct answer: D
Question 9
Mathematics · 4 marks · −1An ellipse has its center at (1, $-$2), one focus at (3, $-$2) and one vertex at (5, $-$2). Then the length of its latus rectum is :
- A.
- B.6
- C.
- D.
Correct answer: B
Explanation: , , : .
Question 10
Mathematics · 4 marks · −1Let the circle intersect -axis at the points A(a, 0), and B(b, 0). Let P(, ), and Q(, ) be two points such that . Then the point of intersection of AQ and BP lies on :
- A.
- B.
- C.
- D.
Correct answer: C
Question 11
Mathematics · 4 marks · −1Considering the principal values of inverse trigonometric functions, the value of the expression is equal to :
- A.
- B.
- C.
- D.
Correct answer: A
Explanation: (), (): .
Question 12
Mathematics · 4 marks · −1Let the ellipse and the hyperbola have the same foci. If e and L respectively denote the eccentricity and the length of the latus rectum of H, then the value of is :
- A.67
- B.296
- C.148
- D.126
Correct answer: B
Explanation: Foci ; : , ; .
Question 13
Mathematics · 4 marks · −1Let A be the focus of the parabola . Let the line intersect the parabola at two distinct points B and C. If the centroid of the triangle ABC is , then is equal to :
- A.41
- B.89
- C.32
- D.80
Correct answer: D
Explanation: , : slope , ; , , .
Question 14
Mathematics · 4 marks · −1Let P be a point in the plane of the vectors and such that P is equidistant from the lines AB and AC. If , then the area of the triangle ABP is :
- A.2
- B.
- C.
- D.
Correct answer: D
Question 15
Mathematics · 4 marks · −1Let Q(a, b, c) be the image of the point P(3, 2, 1) in the line . Then the distance of Q from the line is
- A.8
- B.7
- C.6
- D.5
Correct answer: B
Explanation: Foot , Q ; distance from the second line: vector , projection on is ; .
Question 16
Mathematics · 4 marks · −1Let , . Consider the following two statements : (I) f(x) is discontinous at . (II) f(x) is continous at . Then,
- A.Only (I) is True
- B.Neither (I) nor (II) is True
- C.Both (I) and (II) are True
- D.Only (II) is True
Correct answer: B
Question 17
Mathematics · 4 marks · −1Let denote the greatest integer function. Then is equal to :
- A.
- B.
- C.
- D.
Correct answer: C
Question 18
Mathematics · 4 marks · −1Let be such that . If , where , then is equal to :
- A.-11
- B.-5
- C.-26
- D.-18
Correct answer: A
Question 19
Mathematics · 4 marks · −1Let be the solution of the differential equation , . If , then is equal to :
- A.
- B.
- C.
- D.
Correct answer: D
Explanation: ; .
Question 20
Mathematics · 4 marks · −1Let and be two parabolas. If the area of the bounded region enclosed between and is six times the area of the bounded region enclosed between the line , and , then is equal to :
- A.8
- B.15
- C.6
- D.12
Correct answer: D
Explanation: ; line and : .
Question 21
Mathematics · 4 marks · −1Let and B be two matrices such that . Then the sum of all the elements of is ______
Correct answer: 0
Explanation: with : , , sum 0.
Question 22
Mathematics · 4 marks · −1If , where p and q are positive integers such that , then is equal to ______.
Correct answer: 976
Explanation: Telescopes to : 976.
Question 23
Mathematics · 4 marks · −1Three persons enter in a lift at the ground floor. The lift will go upto 10 floor. The number of ways, in which the three persons can exit the lift at three different floors, if the lift does not stop at first, second and third floors, is equal to ______.
Correct answer: 210
Explanation: Floors 4-10: .
Question 24
Mathematics · 4 marks · −1If the distance of the point P(43, , ), , from the line , along a line with direction ratios 3, $-$1, 0 is , then is equal to ______
Correct answer: 170
Explanation: Foot must be on the line: , so , : 170.
Question 25
Mathematics · 4 marks · −1Let f be a differentiable function satisfying , and let , . If p and q are respectively the points of local minima and local maxima of g, then the value of is equal to ______.
Correct answer: 9
Question 26
Physics · 4 marks · −1In an experiment, a set of reading are obtained as follows - 1.24 mm, 1.25 mm, 1.23 mm, 1.21 mm. The expected least count of the instrument used in recording these readings is ______ mm.
- A.0.01
- B.0.1
- C.0.05
- D.0.001
Correct answer: A
Question 27
Physics · 4 marks · −1The time period of a simple harmonic oscillator is . Measured value of mass (m) of the object is 10 g with an accuracy of 10 mg and time for 50 oscillations of the spring is found to be 60 s using a watch of 2 s resolution. Percentage error in determination of spring constant (k) is ______ %.
- A.7.60
- B.6.76
- C.3.43
- D.3.35
Correct answer: B
Explanation: .
Question 28
Physics · 4 marks · −1As shown in the figure, a spring is kept in a stretched position with some extension by holding the masses 1 kg and 0.2 kg with a separation more than spring natural length and are released. Assuming the horizontal surface to be frictionless, the angular frequency (in SI unit) of the system is :

- A.27
- B.20
- C.5
- D.30
Correct answer: D
Explanation: kg; rad/s.
Question 29
Physics · 4 marks · −1A small block of mass m slides down from the top of a frictionless inclined surface, while the inclined plane is moving towards left with constant acceleration . The angle between the inclined plane and ground is and its base length is L. Assuming that initially the small block is at the top of the inclined plane, the time it takes to reach the lowest point of the inclined plane is ______.

- A.
- B.
- C.
- D.
Correct answer: A
Explanation: In the wedge frame a pseudo force acts to the right, opposing the down-slope motion: ; distance ; .
Question 30
Physics · 4 marks · −1A particle starts moving from time and its coordinate is given as . A. The particle returns to its original position (origin) 0.866 units later B. The particle is 1 unit away from origin at its turning point C. Acceleration of the particle is non-negative D. The particle is 0.5 units away from origin at its turning point E. Particle never turns back as acceleration is non-negative. Choose the correct answer from the options given below :
- A.C, E Only
- B.A, B, C Only
- C.A, C, D Only
- D.A, C Only
Correct answer: B
Explanation: again at ; turning point , ; .
Question 31
Physics · 4 marks · −1When the position vector changes sign as , which one of the following vector will not flip under sign change ?
- A.Linear momentum
- B.Angular momentum
- C.Velocity
- D.Acceleration
Correct answer: B
Explanation: : both factors flip, so does not.
Question 32
Physics · 4 marks · −1Match List - I with List - II. List - I: A. Coefficient of viscosity; B. Surface tension; C. Pressure; D. Surface energy. List - II: I. ; II. ; III. ; IV. . Choose the correct answer from the options given below :
- A.A-I, B-III, C-II, D-IV
- B.A-IV, B-I, C-II, D-III
- C.A-IV, B-III, C-I, D-II
- D.A-I, B-II, C-IV, D-III
Correct answer: C
Question 33
Physics · 4 marks · −1The speed of a longitudinal wave in a metallic bar is 400 m/s. If the density and Young's modulus of the bar material are increased by 0.5% and 1%, respectively then the speed of the wave is changed approximately to ______ m/s.
- A.399
- B.398
- C.402
- D.401
Correct answer: D
Explanation: : , so 401 m/s.
Question 34
Physics · 4 marks · −1The mean free path of a molecule of diameter m at the temperature C and pressure Pa, is given as ______ m. (Given J/K).
- A.
- B.
- C.
- D.
Correct answer: A
Explanation: m.
Question 35
Physics · 4 marks · −1Identify the correct statements : A. Electrostatic field lines form closed loops . B. The electric field lines point radially outward when charge is greater than zero. C. The Gauss - Law is valid only for inverse - square force. D. The workdone in moving a charged particle in a static electric field around a closed path is zero. E. The motion of a particle under Coulomb's force must take place in a plane. Choose the correct answer from the options given below :
- A.A, B, C, D Only
- B.A, C, E Only
- C.B, C, D, E Only
- D.A, B, D, E Only
Correct answer: C
Question 36
Physics · 4 marks · −1Identify the correct statements : A. Effective capacitance of a series combination of capacitors is always smaller than the smallest capacitance of the capacitor in the combination. B. When a dielectric medium is placed between the charged plates of a capacitor, displacement of charges cannot occur due to insulation property of dielectric. C. Increasing of area of capacitor plate or decreasing of thickness of dielectric is an alternate method to increase the capacitance. D. For a point charge, concentric spherical shells centered at the location of the charge are equipotential surfaces. Choose the correct answer from the options given below :
- A.C and D Only
- B.A, B and C Only
- C.B and D Only
- D.A, C and D Only
Correct answer: D
Question 37
Physics · 4 marks · −1A Wheatstone bridge is initially at room temperature and all arms of the bridge have same value of resistances (). When resistance is heated to some temperature, its resistance value has gone up by 10%. The potential difference (after is heated) is ______ V.

- A.0
- B.0.95
- C.2
- D.1.05
Correct answer: B
Explanation: V; V; difference 0.95 V.
Question 38
Physics · 4 marks · −1A long cylindrical conductor with large cross section carries an electric current distributed uniformly over its cross-section. Magnetic field due to this current is : A. maximum at either ends of the conductor and minimum at the midpoint B. maximum at the axis of the conductor C. minimum at the surface of the conductor D. minimum at the axis of the conductor E. same at all points in the cross-section of the conductor. Choose the correct answer from the options given below :
- A.D Only
- B.B, C Only
- C.A, D Only
- D.E Only
Correct answer: A
Explanation: Inside, : zero on the axis, maximum at the surface.
Question 39
Physics · 4 marks · −1Which one of the following is **not** a measurable quantity ?
- A.Voltage difference
- B.Voltage
- C.Resistance
- D.Displacement current
Correct answer: B
Explanation: Only potential differences are measurable; absolute potential depends on the reference.
Question 40
Physics · 4 marks · −1A plane electromagnetic wave is moving in free space with velocity m/s and its electric field is given as V/m, where is the unit vector along -axis. The magnetic field vector of the wave is :
- A. T
- B. T
- C. T
- D. T
Correct answer: A
Explanation: ; , magnitude T.
Question 41
Physics · 4 marks · −1For a transparent prism, if the angle of minimum deviation is equal to its refracting angle, the refractive index n of the prism satisfies.
- A.
- B.
- C.
- D.
Correct answer: A
Explanation: with (so the ray can pass): .
Question 42
Physics · 4 marks · −1A biconvex lens is formed by using two thin planoconvex lenses, as shown in the figure. The refractive index and radius of curved surfaces are also mentioned in figure. When an object is placed on the left side of lens at a distance of 30 cm from the biconvex lens, the magnification of the image will be :

- A.-2.5
- B.+2.5
- C.+2
- D.-2
Correct answer: D
Explanation: ; : , .
Question 43
Physics · 4 marks · −1Number of photons of equal energy emitted per second by a 6 mW laser source operating at 663 nm is ______. (Given : J.s and m/s)
- A.
- B.
- C.
- D.
Correct answer: D
Explanation: .
Question 44
Physics · 4 marks · −1A nucleus has mass number and radius . Another nucleus has mass number and radius . If then is :
- A.1
- B.8
- C.0.5
- D.2
Correct answer: C
Question 45
Physics · 4 marks · −1Two p-n junction diodes and are connected as shown in figure. A and B are input signals and C is the output. The given circuit will function as a ______.

- A.NOR Gate
- B.NAND Gate
- C.AND Gate
- D.OR Gate
Correct answer: C
Explanation: Any input low forward-biases its diode and pulls C low: diode AND gate.
Question 46
Physics · 4 marks · −1A fly wheel having mass 3 kg and radius 5 m is free to rotate about a horizontal axis. A string having negligible mass is wound around the wheel and the loose end of the string is connected to 3 kg mass. The mass is kept at rest initially and released. Kinetic energy of the wheel when the mass descends by 3 m is ______ J. ( m/s)
Correct answer: 30
Explanation: Treating the wheel as a uniform disc: , ; wheel KE J.
Question 47
Physics · 4 marks · −1Two tuning forks A and B are sounded together giving rise to 8 beats in 2 s. When fork A is loaded with wax, the beat frequency is reduced to 4 beats in 2 s. If the original frequency of tuning fork B is 380 Hz then original frequency of tuning fork A is ______ Hz.
Correct answer: 384
Explanation: 4 beats/s initially, falling on loading A, so Hz.
Question 48
Physics · 4 marks · −1An inductor stores 16 J of magnetic field energy and dissipates 32 W of thermal energy due to its resistance when an a.c. current of 2 A (rms) and frequency 50 Hz flows through it. The ratio of inductive reactance to its resistance is ______. ()
Correct answer: 314
Explanation: H; ; .
Question 49
Physics · 4 marks · −1A thermodynamic system is taken through the cyclic process ABC as shown in the figure. The total work done by the system during the cycle ABC is ______ J.

Correct answer: 300
Explanation: Area J (clockwise, positive).
Question 50
Physics · 4 marks · −1A beam of light consisting of wavelengths 650 nm and 550 nm illuminates the Young's double slits with separation of 2 mm such that the interference fringes are formed on a screen, placed at a distance of 1.2 m from the slits. The least distance of a point from the central maximum, where the bright fringes due to both the wavelengths coincide, is ______ m.
Correct answer: 429
Explanation: : for 650 nm; m.
Question 51
Chemistry · 4 marks · −1For the given reaction; CaCO + 2HCl CaCl + HO + CO. If 90 g CaCO is added to 300 mL of HCl which contains 38.55% HCl by mass and has density 1.13 g mL, then which of the following option is **correct** ? Given molar mass of H, Cl, Ca and O are 1, 35.5, 40 and 16 g mol respectively.
- A.60.32 g of HCl remains unreacted
- B.32.85 g of CaCO remains unreacted
- C.97.30 g of HCl reacted
- D.64.97 g of HCl remains unreacted
Correct answer: D
Explanation: HCl g; 0.9 mol CaCO uses 65.7 g HCl; 64.97 g HCl left.
Question 52
Chemistry · 4 marks · −1The wavelength of photon 'A' is 400 nm. The frequency of photon 'B' is s. The wave number of photon 'C' is cm. The correct order of energy of these photons is :
- A.C > B > A
- B.B > A > C
- C.A > C > B
- D.A > B > C
Correct answer: B
Explanation: , , Hz.
Question 53
Chemistry · 4 marks · −1The plot of vs gives a straight line. The intercept and slope respectively are (where K is equilibrium constant).
- A.,
- B.,
- C.,
- D.,
Correct answer: C
Question 54
Chemistry · 4 marks · −1Consider the following aqueous solutions. I. 2.2 g Glucose in 125 mL of solution. II. 1.9 g Calcium chloride in 250 mL of solution. III. 9.0 g Urea in 500 mL of solution. IV. 20.5 g Aluminium sulphate in 750 mL of solution. The **correct** increasing order of boiling point of these solutions will be : [Given : Molar mass in g mol : H=1, C=12, N=14, O=16, Cl=35.5, Ca=40, Al=27 and S=32]
- A.II < III < IV < I
- B.III < I < II < IV
- C.I < II < III < IV
- D.II < III < I < IV
Correct answer: C
Explanation: Particle concentrations: I 0.098, II , III 0.3, IV M. Order I < II < III < IV.
Question 55
Chemistry · 4 marks · −1Observe the following equilibrium in a 1 L flask. A(g) B(g). At T(K), the equilibrium concentrations of A and B are 0.5 M and 0.375 M respectively. 0.1 moles of A is added into the flask and heated to T(K) to establish the equilibrium again. The new equilibrium concentrations (in M) of A and B are respectively
- A.0.742, 0.557.
- B.0.367, 0.275.
- C.0.53, 0.4.
- D.0.557, 0.418.
Correct answer: D
Explanation: ; total 0.975 split : 0.557 and 0.418.
Question 56
Chemistry · 4 marks · −1Match List - I with List - II according to shape. List - I: A. XeO; B. XeF; C. XeOF; D. XeOF. List - II: I. BrF; II. NH; III. [I]; IV. SF. Choose the **correct** answer from the options given below :
- A.A-II, B-III, C-I, D-IV
- B.A-II, B-I, C-III, D-IV
- C.A-II, B-III, C-IV, D-I
- D.A-III, B-II, C-IV, D-I
Correct answer: C
Question 57
Chemistry · 4 marks · −1Consider the elements N, P, O, S, Cl and F. The number of valence electrons present in the elements with most and least metallic character from the above list is respectively.
- A.7 and 5
- B.6 and 7
- C.5 and 6
- D.5 and 7
Correct answer: D
Explanation: Most metallic P (5), least metallic F (7).
Question 58
Chemistry · 4 marks · −1Given below are two statements : Statement I : The increasing order of boiling point of hydrogen halides is HCl < HBr < HI < HF. Statement II : The increasing order of melting point of hydrogen halides is HCl < HBr < HF < HI. In the light of the above statements, choose the **correct** answer from the options given below :
- A.Statement I is true but Statement II is false
- B.Both Statement I and Statement II are false
- C.Both Statement I and Statement II are true
- D.Statement I is false but Statement II is true
Correct answer: C
Explanation: b.p. HCl 189 < HBr 206 < HI 238 < HF 293 K; m.p. HCl 159 < HBr 185 < HF 190 < HI 222 K.
Question 59
Chemistry · 4 marks · −1Consider the following statements about manganate and permanganate ions. Identify the **correct** statements. A. The geometry of both manganate and permanganate ions is tetrahedral. B. The oxidation states of Mn in manganate and permanganate are +7 and +6, respectively. C. Oxidation of Mn(II) salt by peroxodisulphate gives manganate ion as the final product. D. Manganate ion is paramagnetic and permanganate ions is diamagnetic. E. Acidified permanganate ion reduces oxalate, nitrite and iodide ions. Choose the **correct** answer from the options given below :
- A.A, D and E Only
- B.A and D Only
- C.A, C and D Only
- D.A, B and C Only
Correct answer: B
Explanation: E is wrong: permanganate oxidises (not reduces) these ions.
Question 60
Chemistry · 4 marks · −1The correct increasing order of spin-only magnetic moment values of the complex ions [MnBr] (A), [Cu(HO)] (B), [Ni(CN)] (C) and [Ni(HO)] (D) is :
- A.A = B < C < D
- B.A = B < D < C
- C.C = D < B < A
- D.C < B < D < A
Correct answer: D
Explanation: Unpaired electrons: C 0, B 1, D 2, A 5.
Question 61
Chemistry · 4 marks · −1Consider the following reactions: NaBO 2X + Y; CuSO + Y Z + SO; 2Z + 2X + Carbon 2Q + NaBO + CO. The oxidation states of Cu in Z and Q, respectively are :
- A.+2 and +1
- B.+1 and +2
- C.+2 and +2
- D.+1 and +1
Correct answer: A
Explanation: X = NaBO, Y = BO, Z = Cu(BO) (Cu), Q = CuBO (Cu).
Question 62
Chemistry · 4 marks · −1The cyclic cations having the same number of hyperconjugation are : [four substituted cyclohexyl carbocations A, B, C, D shown in the figure]. Choose the **correct** answer from the options given below :

- A.A, C and D only
- B.A and B Only
- C.A and C Only
- D.B and C Only
Correct answer: C
Question 63
Chemistry · 4 marks · −1Identify the **correct** statements : The presence of NO group in benzene ring A. activates the ring towards electrophilic substitutions. B. deactivates the ring towards electrophilic substitutions. C. activates the ring towards nucleophilic substitutions. D. deactivates the ring towards nucleophilic substitutions. Choose the **correct** answer from the options given below :
- A.A and D Only
- B.B and C Only
- C.C and A Only
- D.B and D Only
Correct answer: B
Question 64
Chemistry · 4 marks · −1The reactions which produce alcohol as the product are : A. CH + O ; B. 2CHCH + 3O ; C. (CH)CH ; D. 2CH + O ; E. CHCH=CHCH . Choose the **correct** answer from the options given below :
- A.A and D Only
- B.C and D Only
- C.A, C and E Only
- D.B, D and E Only
Correct answer: B
Explanation: A gives HCHO, B gives acetic acid, E gives acetic acid; C gives tert-butanol, D gives methanol.
Question 65
Chemistry · 4 marks · −1Which of the following reaction is NOT correctly represented ?
- A.Toluene benzyl bromide
- B.Benzenediazonium chloride bromobenzene
- C.Toluene ortho and para bromotoluenes
- D.1-Methylcyclohexene 1-(bromomethyl)cyclohexene
Correct answer: D
Explanation: Allylic radical bromination of 1-methylcyclohexene substitutes mainly at the ring allylic CH, not the methyl.
Question 66
Chemistry · 4 marks · −1The correct order of acidic strength of the major products formed in the given reactions, is : A. PhNH [A]; B. CHCHCHO [B]; C. CH + O [C]; D. PhCHMgBr + CO [D]. Choose the **correct** answer from the options given below :
- A.C > A > D > B
- B.C > B > A > D
- C.A > D > C > B
- D.A > D > B > C
Correct answer: A
Explanation: C = HCOOH (pKa 3.75), A = benzoic acid (4.2), D = phenylacetic acid (4.3), B = propanoic acid (4.87).
Question 67
Chemistry · 4 marks · −1A student performed analysis of aliphatic organic compound 'X' which on analysis gave C = 61.01%, H = 15.25%, N = 23.74%. This compound, on treatment with HNO/HO produced another compound 'Y' which did not contain any nitrogen atom. However, the compound 'Y' upon controlled oxidation produced another compound 'Z' that responded to iodoform test. The structure of 'X' is :
- A.PhCH(CH)NH
- B.(CH)CHNH
- C.CHCHCH(NH)CH
- D.CHCHCHNH
Correct answer: B
Explanation: Empirical CHN; isopropylamine gives propan-2-ol, then acetone (iodoform positive).
Question 68
Chemistry · 4 marks · −1Total number of alkali insoluble solid sulphonamides obtained by reaction of given amines with Hinsberg's reagent is ______. Aniline, N-Methylaniline, Methanamine, N, NDimethylmethanamine, N-Methyl methanamine, Phenylmethanamine, N-propylaniline, N-phenylaniline, N, N-Dimethylaniline, Allyl amine, Isopropyl amine
- A.2
- B.4
- C.5
- D.8
Correct answer: B
Explanation: Secondary amines: N-methylaniline, N-methylmethanamine, N-propylaniline, N-phenylaniline: 4.
Question 69
Chemistry · 4 marks · −1Structures of four disaccharides are given below. Among the given disaccharides, the non-reducing sugar is :

- A.Glucopyranosyl-fructofuranoside (sucrose-type, C1-C2 link)
- B.Pyranose-C1 to C4-pyranose with free anomeric OH (variant 2)
- C.Pyranose-C1 to C4-pyranose with free anomeric OH (variant 3)
- D.Pyranose-C1 to C4-pyranose with free anomeric OH (variant 4)
Correct answer: A
Explanation: Only the sucrose-type structure has no free hemiacetal.
Question 70
Chemistry · 4 marks · −1A student has been given 0.314 g of an organic compound and asked to estimate Sulphur. During the experiment, the student has obtained 0.4813 g of barium sulphate. The percentage of sulphur present in the compound is ______. (Given Molar mass in g mol S : 32, BaSO : 233)
- A.21.05%
- B.48.24%
- C.42.10%
- D.63.15%
Correct answer: A
Explanation: .
Question 71
Chemistry · 4 marks · −1Two positively charged particles and have been accelerated across the same potential difference of 200 keV as shown below. [Given mass of = 1 amu and = 4 amu] The deBroglie wavelength of will be x times of . The value of x is ______ (nearest integer)

Correct answer: 2
Explanation: Same kinetic energy: , .
Question 72
Chemistry · 4 marks · −1For strong electrolyte increases slowly with dilution and can be represented by the equation . Molar conductivity values of the solutions of strong electrolyte AB at 18C are given below : c [mol L] = 0.04, 0.09, 0.16, 0.25 with [S cm mol] = 96.1, 95.7, 95.3, 94.9. The value of constant A based on the above data [in S cm mol/(mol/L)] unit is ______.
Correct answer: 4
Explanation: = 0.2, 0.3, 0.4, 0.5; slope : A = 4.
Question 73
Chemistry · 4 marks · −1A volume of x mL of 5 M NaHCO solution was mixed with 10 mL of 2 M HCO solution to make an electrolytic buffer. If the same buffer was used in the following electrochemical cell to record a cell potential of 235.3 mV, then the value of x = ______ mL (nearest integer). Sn(s) | Sn(OH) (0.5 M) | HSnO (0.05 M) | OH | BiO(s) | Bi(s). Consider upto one place of decimal for intermediate calculations. Given : V, V, pKa(HCO) = 6.11, V, Antilog (1.29) = 19.5
Correct answer: 78
Explanation: Per NTA key x = 78: the cell EMF fixes [OH] and hence pH; Henderson equation with antilog(1.29) = 19.5 gives , mL.
Question 74
Chemistry · 4 marks · −1A B (first reaction); C D (second reaction). Consider the above two first-order reactions. The rate constant for first reaction at 500 K is double of the same at 300 K. At 500 K, 50% of the reaction becomes complete in 2 hour. The activation energy of the second reaction is half of that of first reaction. If the rate constant at 500 K of the second reaction becomes double of the rate constant of first reaction at the same temperature; then rate constant for the second reaction at 300 K is ______ hour (nearest integer).
Correct answer: 5
Explanation: h; ; halving means : .
Question 75
Chemistry · 4 marks · −1The number of isoelectronic species among Sc, Cr, Mn, Co and Fe is 'n'. If 'n' moles of AgCl is formed during the reaction of complex with formula CoCl(en)NH with excess of AgNO solution, then the number of electrons present in the t orbital of the complex is ______.
Correct answer: 6
Explanation: Cr and Mn (22 e each): n = 2, so [CoCl(en)NH]Cl; low-spin Co d: 6 t electrons.