JEE - MAIN OFFICIAL EXAM - 2018 Date: 08 Apr 2018 CODE - C Solutions 1. Ionic equilibrium, 1
2. PRACTICAL ORGANIC CHEMISTRY, To estimate by using kjeldhals method, given organic compound must contain bond. So aniline is ans for given question. 3. Chemical Bonding, Lewis Acids means molecules having incomplete octet configuration is shown by Electron Rich : Octet configuration : 4. Phenols, 5. Volumetric analysis, range of methly orange is Thus it colour changes from yellow to pinkish red. Initially in basic solution is shows yellow color but as we approaches equivalence/end point is color changes to pinkish red. 2
6. Ionic equilibrium, 7. Thermodynamics, 8. P-block, does not undergo thermal decomposition. 3
9. Electrochemistry, mass mole mole of react. 10. Chemical Bonding, radical contains lone pairs in total. lone pair. 11. P-block, White gelatinous ppt. 4
12. Chemical Bonding, Not a viable molecule means that bond order is zero or negative total no. of electrons = 4 13. GOC, is less basic than is least basic. 14. Solid State, In frenkel defect Cations migrate from its lattice position to interstitial sites. 5
15. Chemical Bonding, Covalent bond. Covalent bond. Covalent bond. 16. Di iculty : Di icult Coordination Compounds, Complex Oxidation state of Cr Ligand Nature Neutral Neutral Anionic Neutral 17. Hydrogen & Its compound, Hence Acidic Medium : can be used as oxidant as well as reductant Basic Medium : 6
18. BIOMOLECULES, 19. is reducing agent it can reduce aldehyde and alcohols. AMINES, Human blood is bu er solution. Histamine is Human blood, Histamine amine is in protinated form 20. Environmental Chemistry, The (fluoride) ions make the enamel on teeth much harder by converting hydroxypatite the enamel on the surface of the teeth, into much harder fluropatite 7
21. Di iculty : Di icult Coordination Compounds, 22. Hydrocarbon, It is birch reducing. In birch reduction trans alkenes are formed. 23. Di iculty : Di icult Mole concept,...(1) E.F. of compound 8
24. Phenols, 25. Di iculty : Di icult Ethers, Bulky R-X undergo elimination reaction with 26. Chemical Kinetics, (Exothermic ) Slope graph & are possible 27. Ethers, Phenolic group does not react with 9
28. Di iculty : Di icult Ionic equilibrium, When the solution begins to PPl in Initial in is 29. Chemical Kinetics, 30. Solutions, Thus lesser the no. of particles/ions higher will be the freezing point. 10
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 31. Indefinite integration, 32. Conic Sections, will be chord of contact Hence take 11
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 33. Conic Sections, 34. Vectors, Alternately, vector to & in the plane of will be 12
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 35. Complex Numbers, 36. Area under curve, 37. Binomial Theorem, 38. Sequence & Series, 13
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 39. STATISTICS, Take standard deviation of will be same as standard deviation of 40. Height & Distance, 14
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 41. Ellipse, SETS, RELATION AND FUNCTIONS, will be a inside of a square & B will be inside of an ellipse as shown As point (4,4) & (4,6) are inside the ellipse 42. Permutations & Combinations, 15
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 43. Functions, Let using A.M., G.M. 44. Limits, so, Now taking limits on each So 16
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 45. Definite integration, (1), (2) (using (1) + (2) (3) (4) (3) + (4) 46. Probability, Probability of drawn ball is red 17
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 47. Three Dimensional Geometry, Plane, DR of AB DR of normal of the plane. If be the angle be made by the line segment AB with normal, then Length of projection of on given plane is 48. Trigonometric Ratios & Identities, as, then Hence sum of all values of so value of is 18
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 49. Straight lines, Locus and its Equation, Equation of the line is as lies on the line, so hence locus of the point R is Note that the given option is not the equation of the locus but rather a superset of it as origin does not lie on the locus but it satisfies the given option. 50. Di iculty : Di icult Sequence & Series, similarly Now So 19
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 51. Application of derivatives, Orthogonal trajectory, Parabola, Ellipse, (say) (say) as (using ) 52. Equation of Straight lines, CO-ORDINATE GEOMETRY, which is the diameter of the circle so radius of the circle is 53. ContinuityDi erentiability & Derivatives, has a double root at & at Because at both & have root hence will have a double root. Similarly at & both & have root hence will have a double root. Double root implies function is di erentiable at both. Hence will be an empty set. 20
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 54. Determinants & Matrices, So and Hence order pair of 55. Mathematical reasoning, Alternately T T F T F F F T F F T F F F F T T T F T T F F T F T F T From the truth table, it is clear that 21
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 56. Solutions of simultaneous Equations, Determinants & Matrices, from (i) and (ii) also using (iii) Now, 57. Quadratic Equations, Modulus Function, case I : Case II : Now, so finally, two solutions. 22
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 58. Application of derivatives, Circles, Condition of tangency, Parabola, Slope of tangent to at will be equation of tangent will be which touches the circle distance of from will be radius 59. Di erential Equations,. As 23
RAO IIT ACADEMY / JEE - MAIN OFFICIAL EXAM - 2018 / CODE - C / SOLUTIONS 60. Di iculty : Di icult Three Dimensional Geometry, Family of Planes, The plane will pass through the intersection of &. Hence its equation will be i.e. Similarly this plane will pass through the intersection of hence its equation will be i.e. as (i) & (ii) represent same plane & solving equation of plane is whose distance from origin 61. Wave optics, 24
62. Di iculty : Di icult Modern Physics, 63. Semiconductors, 64. Errors, 25
65. MAGNETISM, 66. Electrostatics, 67. Friction, 26
68. Work,Energy and power, 69. Capacitors, 70. Simple harmonic motion, 27
71. Collisions, fractional loss = loss 28
72. MAGNETISM, 73. Current electricity, 74. Communication systems, 10% of 29
75. Wave optics, 76. Current electricity, 77. Rotational Motion, 30
78. Collisions, kinetic energy is 50% 79. Electromagnetic waves, 80. Alternating current, Quality factor 81. Kinematics, 31
82. Current electricity, 83. Gravitation, 84. Modern Physics, 32
85. Alternating current, 86. Thermodynamics, (a) (b) 33
87. Elasticity, 88. Oscillations and Waves, 89. Kinetic theory of gases, 34
90. Rotational Motion, 35