JEE Main 2024 — 31 Jan Shift 2 (Previous Year Paper)
JEE Main · 2024 · with answers and explanations
- questions
- 89
- Total marks
- 296
- Duration
- 180 minutes
- Negative marking
- −1
Subjects: Mathematics · Physics · Chemistry
Question 1
Mathematics · 4 marks · −1The temperature of a body at time is 160°F and it decreases continuously as per the differential equation , where K is a positive constant. If °F, then is equal to:
- A.85°F
- B.90°F
- C.95°F
- D.80°F
Correct answer: B
Explanation: ; ; °F.
Question 2
Mathematics · 4 marks · −1If the function defined by is one – one and onto, then the distance of the point from the line is:
- A.
- B.
- C.
- D.
Correct answer: C
Explanation: increases on : , ; ; distance .
Question 3
Mathematics · 4 marks · −1If and , then is equal to:
- A.
- B.
- C.
- D.25
Correct answer: A
Explanation: , .
Question 4
Mathematics · 4 marks · −1Let P be a parabola with vertex (2, 3) and directrix . Let an ellipse , , of eccentricity pass through the focus of the parabola P. Then, the square of the length of the latus rectum of E, is:
- A.
- B.
- C.
- D.
Correct answer: C
Explanation: Foot of perpendicular from (2,3) on the directrix is , so focus . With : ; latus rectum , square .
Question 5
Mathematics · 4 marks · −1The number of solutions, of the equation , is:
- A.More than 2
- B.0
- C.1
- D.2
Correct answer: B
Explanation: , impossible.
Question 6
Mathematics · 4 marks · −1Let the mean and the variance of 6 observations a, b, 68, 44, 48, 60 be 55 and 194, respectively. If a > b, then a + 3b is:
- A.210
- B.180
- C.200
- D.190
Correct answer: B
Explanation: , : , .
Question 7
Mathematics · 4 marks · −1A coin is biased so that a head is twice as likely to occur as a tail. If the coin is tossed 3 times, then the probability of getting two tails and one head is:
- A.
- B.
- C.
- D.
Correct answer: B
Explanation: .
Question 8
Mathematics · 4 marks · −1If for some : and then is equal to:
- A.380
- B.372
- C.376
- D.384
Correct answer: B
Explanation: ; ; .
Question 9
Mathematics · 4 marks · −1Let be strictly increasing function such that . Then, the value of is equal to:
- A.0
- B.1
- C.
- D.4
Correct answer: A
Explanation: .
Question 10
Mathematics · 4 marks · −1Let , and respectively denote the centroid, circumcentre and orthocentre of a triangle. Then, the distance of the point from the line measured parallel to the line is:
- A.
- B.
- C.
- D.
Correct answer: B
Explanation: , ; along direction : .
Question 11
Mathematics · 4 marks · −1Let be two functions defined by and . Then, the value of is equal to:
- A.6
- B.10
- C.9
- D.8
Correct answer: D
Explanation: (the parts cancel after substitution); at : .
Question 12
Mathematics · 4 marks · −1The shortest distance, between lines and , where and is the line, passing through the points , and perpendicular to the line , is:
- A.
- B.
- C.
- D.
Correct answer: A
Question 13
Mathematics · 4 marks · −1The number of ways in which 21 identical apples can be distributed among three children such that each child gets at least 2 apples, is:
- A.142
- B.130
- C.136
- D.406
Correct answer: C
Explanation: .
Question 14
Mathematics · 4 marks · −1Let be the mirror image of the point (2, 3, 5) in the line . Then is equal to:
- A.34
- B.31
- C.33
- D.32
Correct answer: C
Explanation: Foot at on ; image foot gives .
Question 15
Mathematics · 4 marks · −1The area of the region enclosed by the parabolas and is equal to:
- A.4
- B.
- C.
- D.6
Correct answer: D
Explanation: Intersections at ; .
Question 16
Mathematics · 4 marks · −1Let , and terms of a non-constant A.P. be respectively the , and terms of a G.P. If the first term of the A.P. is 1, then the sum of its first 20 terms is equal to:
- A.980
- B.970
- C.960
- D.990
Correct answer: B
Explanation: , ; .
Question 17
Mathematics · 4 marks · −1Let and be two complex numbers such that and . Then, equals:
- A.
- B.75
- C.
- D.
Correct answer: B
Explanation: ; with : , modulus 75.
Question 18
Mathematics · 4 marks · −1Consider the function defined by . If and be respectively the number of points at which is not continuous and is not differentiable, then is:
- A.3
- B.0
- C.1
- D.2
Correct answer: C
Explanation: on and beyond; corner at .
Question 19
Mathematics · 4 marks · −1Let a variable line passing through the centre of the circle , meet the positive co-ordinate axes at the points A and B. Then the minimum value of OA + OB, where O is the origin, is equal to:
- A.18
- B.12
- C.20
- D.24
Correct answer: A
Explanation: Through (8, 2): minimum of with is .
Question 20
Mathematics · 4 marks · −1Let A be a real matrix such that , , . Then, the system has.
- A.Exactly two solutions
- B.Unique solutions
- C.Infinitely many solutions
- D.No solution
Correct answer: B
Explanation: Eigenvalues 2, 4, 2; 3 is not an eigenvalue, so is invertible.
Question 21
Mathematics · 4 marks · −1Let be the lengths of three sides of a triangle satisfying the condition . If the set of all possible values of is the interval then is equal to ______.
Correct answer: 36
Question 22
Mathematics · 4 marks · −1Let . Let R be a relation on A defined by if and only if . Let be a symmetric relation on A such that and the number of elements in is n. Then the minimum value of n is ______.
Correct answer: 66
Explanation: has 33 pairs , none symmetric to itself: .
Question 23
Mathematics · 4 marks · −1Let , and be a vector such that and . Then is equal to ______.
Correct answer: 38
Question 24
Mathematics · 4 marks · −1is equal to ______.
Correct answer: 15
Question 25
Mathematics · 4 marks · −1If , then is equal to ______.
Correct answer: 81
Explanation: , , give , ; .
Question 26
Mathematics · 4 marks · −1Let , , and be the vertices of a parallelogram ABCD. If the point C lies on and the point D lies on , then the value of is equal to ______.
Correct answer: 32
Explanation: ; solving gives , ; .
Question 27
Mathematics · 4 marks · −1A line passes through and . The point , where a, b, c are non-negative integers, on the line AB lies at a distance of 21 units, from the point A. The distance between the points and is equal to ______.
Correct answer: 22
Explanation: Unit direction ; ; .
Question 28
Mathematics · 4 marks · −1Let the coefficient of in the expansion of be . If , , then the value of equals ______.
Correct answer: 25
Explanation: The sum is ; at : ; .
Question 29
Mathematics · 4 marks · −1Let A be matrix and det. If , then the remainder when is divided by 9 is equal to ______.
Correct answer: 7
Explanation: ; since depends on , .
Question 30
Mathematics · 4 marks · −1Let be the solution of the differential equation , , . If , then is equal to ______.
Correct answer: 9
Question 31
Physics · 4 marks · −1A gas mixture consists of 8 moles of argon and 6 moles of oxygen at temperature T. Neglecting all vibrational modes, the total internal energy of the system is:
- A.27 RT
- B.21 RT
- C.20 RT
- D.29 RT
Correct answer: A
Explanation: .
Question 32
Physics · 4 marks · −1Given below are two statements: Statement I : Electromagnetic waves carry energy as they travel through space and this energy is equally shared by the electric and magnetic fields. Statement II : When electromagnetic waves strike a surface, a pressure is exerted on the surface. In the light of the above statements, choose the most appropriate answer from the options given below:
- A.Both Statement I and Statement II are correct.
- B.Both Statement I and Statement II are incorrect.
- C.Statement I is incorrect but Statement II is correct.
- D.Statement I is correct but Statement II is incorrect.
Correct answer: A
Question 33
Physics · 4 marks · −1In a photoelectric effect experiment a light of frequency 1.5 times the threshold frequency is made to fall on the surface of photosensitive material. Now if the frequency is halved and intensity is doubled, the number of photo electron emitted will be:
- A.Zero
- B.Quadrupled
- C.Halved
- D.Doubled
Correct answer: A
Explanation: : no emission.
Question 34
Physics · 4 marks · −1The resistance per centimeter of a meter bridge wire is r, with XΩ resistance in left gap. Balancing length from left end is at 40 cm with 25Ω resistance in right gap. Now the wire is replaced by another wire of 2r resistance per centimeter. The new balancing length for same setting will be at :
- A.20 cm
- B.40 cm
- C.80 cm
- D.10 cm
Correct answer: B
Explanation: Balance depends only on the length ratio.
Question 35
Physics · 4 marks · −1Force between two point charges and placed in vacuum at 'r' cm apart is F. Force between them when placed in a medium having dielectric constant K = 5 at 'r/5' cm apart will be:
- A.25F
- B.F/25
- C.5F
- D.F/5
Correct answer: C
Explanation: .
Question 36
Physics · 4 marks · −1The mass of the moon is times the mass of a planet and its diameter is times the diameter of a planet. If the escape velocity on the planet is v, the escape velocity on the moon will be:
- A.
- B.
- C.
- D.
Correct answer: C
Explanation: .
Question 37
Physics · 4 marks · −1A uniform magnetic field of T acts along positive Y-direction. A rectangular loop of sides 20 cm and 10 cm with current of 5A is in Y – Z plane. The current is in anticlockwise sense with reference to negative X axis. Magnitude and direction of the torque is:
- A. N-m along positive X-direction
- B. N-m along positive Y-direction
- C. N-m along positive Z-direction
- D. N-m along negative Z-direction
Correct answer: D
Explanation: A m²; .
Question 38
Physics · 4 marks · −1Consider two physical quantities A and B related to each other as where E, x and t have dimensions of energy, length and time respectively. The dimension of AB is:
- A.
- B.
- C.
- D.
Correct answer: D
Explanation: , ; .
Question 39
Physics · 4 marks · −1The output of the given circuit diagram is:

- A.A B Y: 0 0 0; 1 0 1; 0 1 1; 1 1 0
- B.A B Y: 0 0 0; 1 0 0; 0 1 0; 1 1 1
- C.A B Y: 0 0 0; 1 0 0; 0 1 1; 1 1 0
- D.A B Y: 0 0 0; 1 0 0; 0 1 0; 1 1 0
Correct answer: D
Explanation: for all inputs.
Question 40
Physics · 4 marks · −1The speed of sound in oxygen at S.T.P. will be approximately : (given, R = 8.3 J K, γ = 1.4)
- A.333 m/s
- B.341 m/s
- C.310 m/s
- D.325 m/s
Correct answer: C
Explanation: m/s; nearest listed value 310 m/s.
Question 41
Physics · 4 marks · −1If two vectors and having equal magnitude R are inclined at an angle θ, then :
- A.
- B.
- C.
- D.
Correct answer: A
Question 42
Physics · 4 marks · −1The mass number of nucleus having radius equal to half of the radius of nucleus with mass number 192 is:
- A.20
- B.32
- C.40
- D.24
Correct answer: D
Explanation: : .
Question 43
Physics · 4 marks · −1When unpolarized light is incident at an angle of 60° on a transparent medium from air, the reflected ray is completely polarized. The angle of refraction in the medium is :
- A.30°
- B.45°
- C.60°
- D.90°
Correct answer: A
Question 44
Physics · 4 marks · −1A light string passing over a smooth light fixed pulley connects two blocks of masses and . If the acceleration of the system is g/8, then the ratio masses is:

- A.
- B.
- C.
- D.
Correct answer: A
Explanation: .
Question 45
Physics · 4 marks · −1AN AC voltage is applied to a series LCR circuit which drives a current . The average power dissipated is:
- A.21.6 W
- B.50 W
- C.200 W
- D.173.2 W
Correct answer: B
Explanation: W.
Question 46
Physics · 4 marks · −1A body of mass 2 kg begins to move under the action of a time dependent force given by N. The power developed by the force at the time t is given by:
- A. W
- B. W
- C. W
- D. W
Correct answer: D
Explanation: ; .
Question 47
Physics · 4 marks · −1By what percentage will the illumination of the lamp decrease if the current drops by 20%?
- A.36 %
- B.56%
- C.46%
- D.26%
Correct answer: A
Explanation: : .
Question 48
Physics · 4 marks · −1A small spherical ball of radius r, falling through a viscous medium of negligible density has terminal velocity 'v'. Another ball of the same mass but of radius 2r, falling through the same viscous medium will have terminal velocity:
- A.
- B.
- C.
- D.
Correct answer: D
Explanation: .
Question 49
Physics · 4 marks · −1The measured value of the length of a simple pendulum is 20 cm with 2mm accuracy. The time for 50 oscillations was measured to be 40 seconds with 1 second resolution. From these measurements, the accuracy in the measurement of acceleration due to gravity is N%. The value of N is:
- A.6
- B.8
- C.5
- D.4
Correct answer: A
Explanation: .
Question 50
Physics · 4 marks · −1A nucleus has mass number and volume . Another nucleus has mass number and Volume . If relation between mass number is then ______.
Correct answer: 4
Question 51
Physics · 4 marks · −1Two circular coils P and Q of 100 turns each have same radius of π cm. The currents in P and R are 1A and 2A respectively. P and Q are placed with their planes mutually perpendicular with their centres coincide. The resultant magnetic field induction at the centre of the coils is mT, where ______. [Use T m A]
Correct answer: 20
Explanation: : 2 mT and 4 mT, perpendicular: mT.
Question 52
Physics · 4 marks · −1The time period of simple harmonic motion of mass M in the given figure is , where the value of α is ______.

Correct answer: 12
Explanation: ; .
Question 53
Physics · 4 marks · −1Light from a point source in air falls on a convex curved surface of radius 20 cm and refractive index 1.5. If the source is located at 100 cm from the convex surface, the image will be formed at ______ cm from the object.
Correct answer: 200
Explanation: cm; distance from object 200 cm.
Question 54
Physics · 4 marks · −1In the following circuit, the battery has an emf 2V and an internal resistance of Ω. The power consumption in the entire circuit is ______ W.

Correct answer: 3
Explanation: The network is equivalent to ; W.
Question 55
Physics · 4 marks · −1Two blocks of mass 2kg and 4 kg are connected by a metal wire going over a smooth pulley as show in figure. The radius of wire is m and Young's modulus of the metal is N/m². The longitudinal strain developed in the wire is . The value of α is ______. [Use g = 10 m/s²]

Correct answer: 12
Explanation: N; strain .
Question 56
Physics · 4 marks · −1The distance between charges +q and – q is 2l and between +2q and – 2q is 4l. The electrostatic potential at point P at a distance r from centre O is V, where the value of α is ______. [Use N m² C]

Correct answer: 27
Explanation: Net dipole pointing from −2q side to +2q, i.e. opposite to OP's axial component: .
Question 57
Physics · 4 marks · −1A body of mass 'm' is projected with a speed 'u' making an angle of 45° with the ground. The angular momentum of the body about the point of projection, at the highest point is expressed as . The value of 'X' is ______.
Correct answer: 8
Explanation: .
Question 58
Physics · 4 marks · −1Two identical spheres each of mass 2kg and radius 50 cm are fixed at the ends of a light rod so that the separation between the centres is 150 cm. then, moment of inertia of the system about an axis perpendicular to the rod and passing through its middle point is kg m², where the value of x is ______.
Correct answer: 53
Explanation: .
Question 59
Physics · 4 marks · −1The magnetic flux φ (in weber) linked with a closed circuit of resistance 8Ω varies with time (in seconds) as . The induced current in the circuit at t = 2s is ______ A.
Correct answer: 2
Explanation: V; A.
Question 60
Chemistry · 4 marks · −1Given below are two statements : Statements I : solid undergoes disproportionation reaction under alkaline conditions to from and . Statement II : can undergo disproportionation reaction under acidic condition. In the light of the above statements, choose the most appropriate answer from the options given below:
- A.Both statement I and statement II are incorrect
- B.Statement I is incorrect but statement II is correct
- C.Both statement I and statement II are correct
- D.Statement I is correct but statement II is incorrect
Correct answer: D
Explanation: Cl is in its highest state (+7) in perchlorate.
Question 61
Chemistry · 4 marks · −1Which of the following is least ionic ?
- A.KCl
- B.
- C.AgCl
- D.
Correct answer: C
Question 62
Chemistry · 4 marks · −1The four quantum numbers for the electron in the outer most orbital of potassium (atomic no. 19) are:
- A.n = 3, l = 0, m = 1, s = +1/2
- B.n = 2, l = 0, m = 0, s = +1/2
- C.n = 4, l = 0, m = 0, s = +1/2
- D.n = 4, l = 2, m = −1, s = +1/2
Correct answer: C
Question 63
Chemistry · 4 marks · −1Identify major product 'P' formed in the following reaction. Benzene + Benzoyl chloride 'P' (Major Product)
- A.Benzaldehyde
- B.Benzophenone
- C.Acetophenone
- D.3-Phenoxybenzoyl chloride
Correct answer: B
Question 64
Chemistry · 4 marks · −1The azo-dye (Y) formed in the following reaction is. Sulphanilic acid + + X. X + 1-naphthylamine → Y

- A. naphthyl with on the other ring
- B.bis-azo compound (two -sulphophenylazo groups on naphthalene)
- C.structure with two sulphonic-acid-bearing rings and two azo links
- D. at C-4 of 1-naphthylamine (4-amino-1-naphthyl azo, para to )
Correct answer: D
Explanation: Diazotised sulphanilic acid couples para to the NH of 1-naphthylamine (Griess–Ilosvay test).
Question 65
Chemistry · 4 marks · −1The fragrance of flowers is due to the presence of some steam volatile organic compounds called essential oils. These are generally insoluble in water at room temperature but are miscible with water vapour in vapour phase. A suitable method for the extraction of these oils from the flower is:
- A.Crystallisation
- B.Steam distillation
- C.Distillation under reduced pressure
- D.Distillation
Correct answer: B
Question 66
Chemistry · 4 marks · −1Identify the name reaction. Benzene Benzaldehyde
- A.Gatterman – Koch Reaction
- B.Etard Reaction
- C.Stephen Reaction
- D.Rosenmund Reduction
Correct answer: A
Question 67
Chemistry · 4 marks · −1Major product of the following reaction is: 1-Methylcyclopentene ?

- A.C1 carries H and Cl, C2 carries D and
- B.C1 carries D and H... (D, up on adjacent carbons; H, Cl down): D on C-2 with H, and Cl on C-1
- C.Cl and D up, H and down on adjacent carbons
- D.D and Cl up, H and down on adjacent carbons
Correct answer: B
Explanation: D adds to C-2 giving the tertiary cation at C-1, which takes Cl: 1-chloro-2-deuterio-1-methylcyclopentane.
Question 68
Chemistry · 4 marks · −1The correct order of reactivity in electrophilic substitution reaction of the following compounds is: A = benzene, B = toluene, C = chlorobenzene, D = nitrobenzene
- A.A > B > C > D
- B.B > C > A > D
- C.B > A > C > D
- D.D > C > B > A
Correct answer: C
Question 69
Chemistry · 4 marks · −1Select the option with correct property:
- A. and both Paramagnetic
- B. Diamagnetic, Paramagnetic
- C. and both Diamagnetic
- D. Diamagnetic, Paramagnetic
Correct answer: D
Question 70
Chemistry · 4 marks · −1Given below are two statements: Statement I : Aniline reacts with con. , followed by heating at 453-473K gives p-aminobenzene sulphonic acid, which gives blood red colour in the 'Lassaigne's test' Statement II : In Friedel – Craft's alkylation and acylation reactions, aniline forms salt with the catalyst. Due to this, nitrogen of aniline aquires a positive charge and acts as deactivating group. 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.Both statement I and statement II are true
- C.Statement I is true but statement II is false
- D.Both statement I and statement II are false
Correct answer: B
Question 71
Chemistry · 4 marks · −1. The correct relationship between , α and equilibrium pressure P is:
- A.
- B.
- C.
- D.
Correct answer: D
Explanation: Moles ; total ; .
Question 72
Chemistry · 4 marks · −1Consider the following elements. A' and B' are in the same period (B' to the right of A'); C' and D' are below A' and B' respectively in the next period (Group ↓, Period →). Which of the following is/are true about A', B', C' and D'? A. Order of atomic radii : B' < A' < D' < C' B. Order of metallic character : B' < A' < D' < C' C. Size of the element : D' < C' < B' < A' D. Order of ionic radii : B' < A' < D' < C' Choose the correct answer from the options given below:
- A.A only
- B.A and B only
- C.A, B and D only
- D.B, C and D only
Correct answer: C
Question 73
Chemistry · 4 marks · −1Identify A and B in the following reaction sequence. Bromobenzene A B

- A.A = 2-bromo-1,3,5-trinitrobenzene (picryl bromide); B = 2,4,6-trinitrophenol
- B.A = 1-bromo-2,4-dinitrobenzene; B = 2-bromobenzene-1,4-diol-type product
- C.A = nitrobenzene; B = 3-nitrophenol
- D.A = 1-bromo-4-nitrobenzene; B = 2-bromo-5-nitrophenol
Correct answer: A
Question 74
Chemistry · 4 marks · −1Given below are two statements : Statement I : Group 13 trivalent halides get easily hydrolyzed by water due to their covalent nature. Statement II : upon hydrolysis in acidified aqueous solution forms octahedral ion. In the light of the above statements, choose the correct answer from the option below :
- A.Statement I is false but statement II is true
- B.Both statement I and statement II are true
- C.Statement I is true but statement II is false
- D.Both statement I and statement II are false
Correct answer: B
Question 75
Chemistry · 4 marks · −1Identify structure of 2, 3-dibromo-1-phenylpentane.

- A. (Br on C-2 and C-3)
- B.
- C.Skeletal structure with both Br drawn on alternate chain carbons (1,3-pattern)
- D.
Correct answer: A
Question 76
Chemistry · 4 marks · −1Choose the correct statements from the following. A. is an oil at room temperature B. reacts with acid to give C. CrO is a basic oxide D. does not react with acid Choose the correct answer from the options given below :
- A.A, B and C only
- B.B and C only
- C.A and C only
- D.A, B and D only
Correct answer: C
Explanation: VO gives VO in acid; VO is amphoteric.
Question 77
Chemistry · 4 marks · −1Match List I with List II List I (Complex ion): A. ; B. ; C. ; D. List II (Electronic Configuration): I. ; II. ; III. ; IV. Choose the correct answer from the options given below :
- A.A – III, B – II, C – IV, D – I
- B.A – IV, B – III, C – I, D – II
- C.A – IV, B – I, C – II, D – III
- D.A – II, B – III, C – IV, D – I
Correct answer: D
Question 78
Chemistry · 4 marks · −1Choose the correct statement from the following . A. All group 16 elements form oxides of general formula and where E = S, Se, Te and Po. Both the types of oxides are acidic in nature. B. is an oxidising agent while is reducing in nature. C. The reducing property decreases from to down the group. D. The ozone molecule contains five lone pairs of electrons. Choose the correct answer from the option given below :
- A.A and D only
- B.C and D only
- C.B and C only
- D.A and B only
Correct answer: D
Question 79
Chemistry · 4 marks · −1A sample of and weighed 2.21 g is ignited to constant weight of 1.152 g. The composition of mixture is: (Given molar mass in g mol : 100, : 84)
- A.1.187 g + 1.023 g
- B.1.023 g + 1.187 g
- C.1.187 g + 1.187 g
- D.1.023 g + 1.023 g
Correct answer: A
Explanation: g.
Question 80
Chemistry · 4 marks · −1If 5 moles of an ideal gas expands from 10 L to a volume of 100 L at 300 K under isothermal and reversible condition then work, w, is – xJ. The value of x is ______. (Given R = 8.314 J K mol)
Correct answer: 28721
Explanation: J.
Question 81
Chemistry · 4 marks · −1From the vitamins A, B, B, B, C, D, E and K, the number of vitamins that can be stored in our body is ______.
Correct answer: 5
Explanation: Fat-soluble A, D, E, K plus B.
Question 82
Chemistry · 4 marks · −1Number of moles of H ions required by 1 mole of to oxidise oxalate ion to is ______.
Correct answer: 4
Explanation: : 8 per MnO.
Question 83
Chemistry · 4 marks · −1The molarity of 1 L orthophosphoric acid () having 70% purity by weight (specific gravity 1.54 g cm) is ______ M. (Molar mass of = 98 g mol)
Correct answer: 11
Explanation: .
Question 84
Chemistry · 4 marks · −1A diatomic molecule has a dipole moment of 1.2 D. If the bond distance is 1Å, then fractional charge on each atom is ______ esu. (Given 1D = esu cm)
Correct answer: 0
Explanation: esu, i.e. 0 in units of esu (nearest integer).
Question 85
Chemistry · 4 marks · −1The value of conductivity of some materials at 298.15K in S m are , , , 3.91, , , . The number of conductors among the materials is ______.
Correct answer: 4
Question 86
Chemistry · 4 marks · −1r = k[A] for a reaction, 50% of A is decomposed in 120 minutes. The time taken for 90% decomposition of A is ______ minutes.
Correct answer: 399
Explanation: .
Question 87
Chemistry · 4 marks · −1Number of isomeric products formed by monochlorination of 2-methylbutane in presence of sunlight is ______.
Correct answer: 6
Explanation: Four constitutional isomers, two of which are chiral: 6 including stereoisomers.
Question 88
Chemistry · 4 marks · −1A compound (x) with molar mass 108 g mol undergoes acetylation to give product with molar mass 192 g mol. The number of amino groups in the compound (x) is ______.
Correct answer: 2
Explanation: Each acetylation adds 42: .
Question 89
Chemistry · 4 marks · −1In the reaction of potassium dichromate, potassium chloride and sulfuric acid (conc.), the oxidation state of the chromium in the product is (+) ______.
Correct answer: 6
Explanation: CrOCl: +6.