JEE Main 2021 (Online) 20th July Morning Shift
JEE Main / 90 questions
2026Tue, Jul 20, 2021 3:30 AM90 PYQs
1Alcohols Phenols And Ethers
In the given reaction
3-Bromo-2, 2-dimethyl butane \(\buildrel {{C_2}{H_5}OH} \over \longrightarrow \mathop {'A'}\limits_{(Major\,\Pr oduct)}\) Product A is :
3-Bromo-2, 2-dimethyl butane \(\buildrel {{C_2}{H_5}OH} \over \longrightarrow \mathop {'A'}\limits_{(Major\,\Pr oduct)}\) Product A is :
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2Alcohols Phenols And Ethers
To synthesize 1.0 mole of 2-methylpropan-2-ol from Ethylethanoate ___________ equivalents of CH3MgBr Reagent will be required. (Integer value)
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3Aldehydes Ketones And Carboxylic Acids
Which among the above compound/s does/do not form Silver mirror when treated with Tollen's reagent?
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4Basics Of Organic Chemistry
Among the given species the Resonance stabilised carbocations are :
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5Biomolecules
Identify the incorrect statement from the following
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6Chemical Bonding And Molecular Structure
The number of lone pairs of electrons on the central I atom in I\(_3^ -\) is ____________.
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7Chemical Equilibrium
2SO2(g) + O2(g) \(\rightleftharpoons\) 2SO3(g)In an equilibrium mixture, the partial pressures are PSO3 = 43 kPa; PO2 = 530 Pa and PSO2 = 45 kPa. The equilibrium constant KP = ___________ \(\times\) 10\(-\)2. (Nearest integer)
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8Chemical Kinetics And Nuclear Chemistry
The inactivation rate of a viral preparation is proportional to the amount of virus. In the first minute after preparation, 10% of the virus is inactivated. The rate constant for viral inactivation is ___________ \(\times\) 10\(-\)3 min$$-$...
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9Chemistry In Everyday Life
Green chemistry in day-to-day life is in the use of :
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10Compounds Containing Nitrogen
The correct structure of Rhumann's Purple, the compound formed in the reaction of ninhydrin with proteins is :
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11Compounds Containing Nitrogen
Compound A is converted to B on reaction with CHCl3 and KOH. The compound B is toxic and can be decomposed by C. A, B and C respectively are :
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12Compounds Containing Nitrogen
The number of nitrogen atoms in a semicarbazone molecule of acetone is ______________.
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13Coordination Compounds
According to the valence bond theory the hybridization of central metal atom is dsp2 for which one of the following compounds?
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14Coordination Compounds
The correct order of intensity of colors of the compounds is :
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15Coordination Compounds
The spin-only magnetic moment value for the complex [Co(CN)6]4\(-\) is __________ BM.[At. no. of Co = 27]
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16Hydrocarbons
For above chemical reactions, identify the correct statement from the following :
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17Hydrogen
Given below are two statements : One is labelled as Assertion A and other is labelled as Reason R. Assertion A : The dihedral angles in H2O2 in gaseous phase is 90.2\(^\circ\) and in solid phase is 111.5\(^\circ\).Reason R : The change in d...
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18Isolation Of Elements
The metal that can be purified economically by fractional distillation method is :
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19P Block Elements
The species given below that does NOT show disproportionation reaction is :
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20P Block Elements
Chemical nature of the nitrogen oxide compound obtained from a reaction of concentrated nitric acid and P4O10 (in 4 : 1 ratio) is :
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21Polymers
Orlon fibres are made up of :
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22Practical Organic Chemistry
An inorganic Compound 'X' on treatment with concentrated H2SO4 produces brown fumes and gives dark brown ring with FeSO4 in presence of concentrated H2SO4. Also Compound 'X' gives precipitate 'Y', when its solution in dilute HCl is treated ...
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23S Block Elements
The set in which compounds have different nature is :
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24S Block Elements
A s-block element (M) reacts with oxygen to form an oxide of the formula MO2. The oxide is pale yellow in colour and paramagnetic. The element (M) is :
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25Solid State
Given below are two statements. One is labelled as Assertion A nd the other is labelled as Reason R.Assertion A : Sharp glass edge becomes smooth on heating it upto its melting point.Reason R : The viscosity of glass decreases on melting.Ch...
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26Solutions
At 20\(^\circ\) C, the vapour pressure of benzene is 70 torr and that of methyl benzene is 20 torr. The mole fraction of benzene in the vapour phase at 20\(^\circ\) above an equimolar mixture of benzene and methyl benzene is _____________ $...
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27Some Basic Concepts Of Chemistry
250 mL of 0.5 M NaOH was added to 500 mL of 1 M HCl. The number of unreacted HCl molecules in the solution after complete reaction is ___________ \(\times\) 1021. (Nearest integer)(NA = 6.022 \(\times\) 1023)
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28Some Basic Concepts Of Chemistry
An average person needs about 10000 kJ energy per day. The amount of glucose (molar mass = 180.0 g mol\(-\)1) needed to meet this energy requirement is ____________ g.(Use : \(\Delta\)CH(glucose) = \(-\)2700 kJ mol\(-\)1)
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29Structure Of Atom
The Azimuthal quantum number for the valence electrons of Ga+ ion is ___________.(Atomic number of Ga = 31)
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30Surface Chemistry
The conditions given below are in the context of observing Tyndall effect in colloidal solutions :(A) The diameter of the colloidal particles is comparable to the wavelength of light used.(B) The diameter of the colloidal particles is much ...
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313d Geometry
Let P be a plane passing through the points (1, 0, 1), (1, \(-\)2, 1) and (0, 1, \(-\)2). Let a vector \(\overrightarrow a = \alpha \widehat i + \beta \widehat j + \gamma \widehat k\) be such that \(\overrightarrow a\) is parallel to the ...
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32Application Of Derivatives
Let \(A = [{a_{ij}}]\) be a 3 \(\times\) 3 matrix, where \({a_{ij}} = \left\{ {\matrix{
1 & , & {if\,i = j} \cr
{ - x} & , & {if\,\left| {i - j} \right| = 1} \cr
{2x + 1} & , & {otherwise.} \cr
} } \right.\)Let a function f...
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33Application Of Derivatives
Let 'a' be a real number such that the function f(x) = ax2 + 6x \(-\) 15, x \(\in\) R is increasing in \(\left( { - \infty ,{3 \over 4}} \right)\) and decreasing in \(\left( {{3 \over 4},\infty } \right)\). Then the function g(x) = ax2 $$-$...
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34Area Under The Curves
Let T be the tangent to the ellipse E : x2 + 4y2 = 5 at the point P(1, 1). If the area of the region bounded by the tangent T, ellipse E, lines x = 1 and x = \(\sqrt 5\) is \(\alpha\)\(\sqrt 5\) + \(\beta\) + \(\gamma\) cos\(-\)1$$\left( ...
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35Binomial Theorem
The coefficient of x256 in the expansion of (1 \(-\) x)101 (x2 + x + 1)100 is :
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36Binomial Theorem
The number of rational terms in the binomial expansion of \({\left( {{4^{{1 \over 4}}} + {5^{{1 \over 6}}}} \right)^{120}}\) is _______________.
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37Complex Numbers
If z and \(\omega\) are two complex numbers such that \(\left| {z\omega } \right| = 1\) and \(\arg (z) - \arg (\omega ) = {{3\pi } \over 2}\), then \(\arg \left( {{{1 - 2\overline z \omega } \over {1 + 3\overline z \omega }}} \right)\) is :...
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38Definite Integration
Let a be a positive real number such that \(\int_0^a {{e^{x - [x]}}} dx = 10e - 9\) where [ x ] is the greatest integer less than or equal to x. Then a is equal to:
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39Definite Integration
The value of the integral \(\int\limits_{ - 1}^1 {{{\log }_e}(\sqrt {1 - x} + \sqrt {1 + x} )dx}\) is equal to:
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40Differential Equations
Let y = y(x) be the solution of the differential equation \(x\tan \left( {{y \over x}} \right)dy = \left( {y\tan \left( {{y \over x}} \right) - x} \right)dx\), \(- 1 \le x \le 1\), \(y\left( {{1 \over 2}} \right) = {\pi \over 6}\). Then t...
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41Differential Equations
Let y = y(x) be the solution of the differential equation \({e^x}\sqrt {1 - {y^2}} dx + \left( {{y \over x}} \right)dy = 0\), y(1) = \(-\)1. Then the value of (y(3))2 is equal to :
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42Functions
Let [ x ] denote the greatest integer \(\le\) x, where x \(\in\) R. If the domain of the real valued function \(f(x) = \sqrt {{{\left| {[x]} \right| - 2} \over {\left| {[x]} \right| - 3}}}\) is (\(-\) \(\infty\), a) \(]\cup\) [b, c) $$\cup...
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43Inverse Trigonometric Functions
The number of real roots of the equation \({\tan ^{ - 1}}\sqrt {x(x + 1)} + {\sin ^{ - 1}}\sqrt {{x^2} + x + 1} = {\pi \over 4}\) is :
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44Limits Continuity And Differentiability
Let a function f : R \(\to\) R be defined as \(f(x) = \left\{ {\matrix{
{\sin x - {e^x}} & {if} & {x \le 0} \cr
{a + [ - x]} & {if} & {0 < x < 1} \cr
{2x - b} & {if} & {x \ge 1} \cr
} } \right.\) where [ x ] is the greatest...
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45Limits Continuity And Differentiability
If the value of \(\mathop {\lim }\limits_{x \to 0} {(2 - \cos x\sqrt {\cos 2x} )^{\left( {{{x + 2} \over {{x^2}}}} \right)}}\) is equal to ea, then a is equal to __________.
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46Mathematical Reasoning
The Boolean expression \((p \wedge \sim q) \Rightarrow (q \vee \sim p)\) is equivalent to :
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47Matrices And Determinants
Let \(A = \left[ {\matrix{
2 & 3 \cr
a & 0 \cr
} } \right]\), a\(\in\)R be written as P + Q where P is a symmetric matrix and Q is skew symmetric matrix. If det(Q) = 9, then the modulus of the sum of all possible values of deter...
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48Matrices And Determinants
Let \(A = \left( {\matrix{
1 & { - 1} & 0 \cr
0 & 1 & { - 1} \cr
0 & 0 & 1 \cr
} } \right)\) and B = 7A20 \(-\) 20A7 + 2I, where I is an identity matrix of order 3 \(\times\) 3. If B = [bij], then b13is equal to ___________...
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49Matrices And Determinants
Let a, b, c, d in arithmetic progression with common difference \(\lambda\). If \(\left| {\matrix{
{x + a - c} & {x + b} & {x + a} \cr
{x - 1} & {x + c} & {x + b} \cr
{x - b + d} & {x + d} & {x + c} \cr
} } \right| = 2\), t...
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50Parabola
Let the tangent to the parabola S : y2 = 2x at the point P(2, 2) meet the x-axis at Q and normal at it meet the parabola S at the point R. Then the area (in sq. units) of the triangle PQR is equal to :
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