Seven capacitors, each of capacitance 2μ F , are to be connected in a configuration to obtain an effective capacitance of ((6)/(13) )μ F . Which of the combinations, shown in figures below, will achieve the desired value?

((6)/(13) )μ F obtained by three capacitors in parallel in series with four capacitors in series

An amplitude modulated signal is plotted below: Which one of the following best describes the above signal?

(9 + (2π × 10^4t ) ) (2.5π × 10^5t )V

JEE Main 2019 January 11, Shift 2 Question Paper with Solutions

All 90 questions from the JEE Main 2019 (January 11, Shift 2) shift — Physics (30), Chemistry (30) and Mathematics (30) — with the correct answer and a step-by-step solution for every question.

Physics PYQs 2019 Chemistry PYQs 2019 Mathematics PYQs 2019

Chemistry30 questions

Q31Single correctSome Basic Concepts in Chemistry

25 mL of the given HCl solution requires 30 mL of 0.1M sodium carbonate solution. What is the volume of this HCl solution required to titrate 30 mL of 0.2M aqueous NaOH solution?

(A)

\displaystyle 25\ \text{mL}

(B)

\displaystyle 75\ \text{mL}

(C)

\displaystyle 50\ \text{mL}

(D)

\displaystyle 12.5\ \text{mL}

Q32Single correctAtomic Structure

The de Broglie wavelength (

\lambda

) associated with a photoelectron varies with the frequency (v) of the incident radiation as,[

v_0

is threshold frequency]:

(A)

\displaystyle \lambda \propto \dfrac{1}{(v-v_0)}

(B)

\displaystyle \lambda \propto \dfrac{1}{(v-v_0)^{\frac{1}{4}}}

(C)

\displaystyle \lambda \propto \dfrac{1}{(v-v_0)^{\frac{3}{2}}}

(D)

\displaystyle \lambda \propto \dfrac{1}{(v-v_0)^{\frac{1}{2}}}

Q33Single correctClassification of Elements and Periodicity in Properties

The correct option with respect to the Pauling electronegativity values of the elements is:

(A)

\displaystyle \text{Te} > \text{Se}

(B)

\displaystyle \text{Ga} < \text{Ge}

(C)

\displaystyle \text{Si} < \text{Al}

(D)

\displaystyle \text{P} > \text{S}

Q34Single correctChemical Thermodynamics

The reaction

\text{MgO(s)} + \text{C(s)} \rightarrow \text{Mg(s)} + \text{CO(g)}

, for which

\Delta\text{H}^{\circ} = +491.1\ \text{kJ mol}^{-1}

and

\Delta\text{S}^{\circ} = 198.0\,\text{JK}^{-1}\,\text{mol}^{-1}

is not feasible at 298 K. Temperature above which reaction will be feasible is

(A)

\displaystyle 2040.5\ \text{K}

(B)

\displaystyle 1890.0\ \text{K}

(C)

\displaystyle 2480.3\ \text{K}

(D)

\displaystyle 2380.5\ \text{K}

Q35Single correctChemical Thermodynamics

The standard reaction Gibbs energy for a chemical reaction at an absolute temperature T is given by

\Delta G^{\circ} = A - BT

where A and B are non-zero constants. Which of the following is true about this reaction?

(A)

Exothermic if

\displaystyle B < 0

(B)

Exothermic if

\displaystyle A > 0

(C)

Endothermic if

\displaystyle A < 0

and

\displaystyle B > 0

(D)

Exothermic if

\displaystyle A > 0

and

\displaystyle B < 0

Q36Single correctEquilibrium

For the equilibrium

2\text{H}_2\text{O} \rightleftharpoons \text{H}_3\text{O}^+ + \text{OH}^-

; the value of

\Delta G^{\circ}

at 298 K is approximately:

(A)

\displaystyle 100\ \text{kJ mol}^{-1}

(B)

\displaystyle -80\ \text{kJ mol}^{-1}

(C)

\displaystyle 80\ \text{kJ mol}^{-1}

(D)

\displaystyle -100\ \text{kJ mol}^{-1}

Q37Single correctp-Block Elements

Match the following items in column I with the corresponding items in column II.

Column-I	Column-II
(i). $\text{Na}_2\text{CO}_3.10\text{H}_2\text{O}$	(A). Portland cement ingredient
(ii). $\text{Mg(HCO}_3)_2$	(B). Castner-Kellner process
(iii). $\text{NaOH}$	(C). Solvay process
(iv). $\text{Ca}_3\text{Al}_2\text{O}_6$	(D). Temporary hardness

(A)

(i)

\displaystyle \rightarrow

(B); (ii)

\displaystyle \rightarrow

(C); (iii)

\displaystyle \rightarrow

(A); (iv)

\displaystyle \rightarrow

(D)

(B)

(i)

\displaystyle \rightarrow

(C); (ii)

\displaystyle \rightarrow

(B); (iii)

\displaystyle \rightarrow

(D); (iv)

\displaystyle \rightarrow

(A)

(C)

(i)

\displaystyle \rightarrow

(D); (ii)

\displaystyle \rightarrow

(A); (iii)

\displaystyle \rightarrow

(B); (iv)

\displaystyle \rightarrow

(C)

(D)

(i)

\displaystyle \rightarrow

(C); (ii)

\displaystyle \rightarrow

(D); (iii)

\displaystyle \rightarrow

(B); (iv)

\displaystyle \rightarrow

(A)

Q38Single correctp-Block Elements

The hydride that is NOT electron deficient is:

(A)

\displaystyle \text{SiH}_4

(B)

\displaystyle \text{B}_2\text{H}_6

(C)

\displaystyle \text{GaH}_3

(D)

\displaystyle \text{AlH}_3

Q39Single correctp-Block Elements

The relative stability of +1 oxidation state of group 13 elements follows the order

(A)

\displaystyle \text{Al} < \text{Ga} < \text{Tl} < \text{In}

(B)

\displaystyle \text{T1} < \text{In} < \text{Ga} < \text{Al}

(C)

\displaystyle \text{Ga} < \text{Al} < \text{ln} < \text{Tl}

(D)

\displaystyle \text{Al} < \text{Ga} < \text{In} < \text{Tl}

Q40Single correctSome Basic Principles of Organic Chemistry

Which of the following compounds reacts with ethylmagnesium bromide and also decolourizes bromine water solution?

(A)

A benzene ring with two ortho substituents: a nitrile group (CN) and an acetyl group (C(=O)CH3, methyl ketone).

(B)

A benzene ring with two ortho substituents: a nitrile group (CN) and a CH2-CO2CH3 group (methyl ester of an acetic acid chain, methyl 2-(2-cyanophenyl)acetate side chain drawn as CH2 - CO2CH3).

(C)

A benzene ring with two ortho substituents: a methoxy group (OCH3) and a vinyl group drawn as CH=CH2 (CH double bonded to CH2).

(D)

A benzene ring with two ortho substituents: a hydroxyl group (OH) and a vinyl group (CH=CH2), that is 2-vinylphenol (ortho-hydroxystyrene).

Q41Single correctOrganic Compounds Containing Halogens

Which of the following compounds will produce a precipitate with AgN

O_3

(A)

A pyridine ring (six-membered aromatic ring with one nitrogen at the bottom) bearing a bromine atom at the 3-position, that is 3-bromopyridine.

(B)

A seven-membered ring (cycloheptatriene) with three alternating carbon-carbon double bonds and one sp3 carbon at the top bearing a bromine atom, that is 7-bromocyclohepta-1,3,5-triene.

(C)

A benzene ring (six-membered aromatic ring with three double bonds) bearing a bromine atom, that is bromobenzene.

(D)

A cyclohexane ring (saturated six-membered ring, no double bonds) bearing a bromine atom at the top, that is bromocyclohexane.

Q42Single correctp-Block Elements

Taj Mahal is being slowly disfigured and discoloured. This is primarily due to

(A)

Global warming

(B)

Acid rain

(C)

Water pollution

(D)

Soil pollution

Q43Single correctp-Block Elements

The higher concentration of which gas in air can cause stiffnes of flower buds?

(A)

\displaystyle \text{NO}

(B)

\displaystyle \text{CO}_2

(C)

\displaystyle \text{SO}_2

(D)

\displaystyle \text{CO}

Q44Single correctSome Basic Concepts in Chemistry

The radius of the largest sphere which fits properly at the centre of the edge of a body centred cubic unit cell is : (Edge length is represented by 'a')

(A)

\displaystyle 0.027\ a

(B)

\displaystyle 0.047\ a

(C)

\displaystyle 0.134a

(D)

\displaystyle 0.067\ a

Q45Single correctSolutions

\text{K}_2\text{HgI}_4

is 40% ionised in aqueous solution. The value of its van't Hoff factor (i) is:

(A)

\displaystyle 1.6

(B)

\displaystyle 1.8

(C)

\displaystyle 20

(D)

\displaystyle 22

Q46Single correctRedox Reactions and Electrochemistry

Given the equilibrium constant:

\text{K}_\text{C}

of the reaction:

\text{Cu(s)}+2\text{Ag}^{+}\text{(aq)}\rightarrow\text{Cu}^{2+}\text{(aq)}+2\text{Ag(s)}

10\times10^{15}

, calculate the

E^{0}_{\text{cell}}

of this reaction at 298 K

\left[2.303\frac{\text{RT}}{\text{F}}\ \text{at}\ 298\ \text{K}=0.059\ \text{V}\right]

(A)

\displaystyle 0.04736\ \text{mV}

(B)

\displaystyle 0.4736\ \text{mV}

(C)

\displaystyle 0.4736\ \text{V}

(D)

\displaystyle 0.04736\ \text{V}

Q47Single correctChemical Kinetics

The reaction

2\text{X}\rightarrow\text{B}

is a zeroth order reaction. If the initial concentration of X is 0.2M, the half-life is 6 h. When the initial concentration of X is 0.5M, the time required to reach its final concentration of 0.2M will be

(A)

\displaystyle 9.0\ \text{h}

(B)

\displaystyle 12.0\ \text{h}

(C)

\displaystyle 18.0\ \text{h}

(D)

\displaystyle 7.2\ \text{h}

Q48Single correctSome Basic Concepts in Chemistry

Among the colloids cheese (C), milk (M) and smoke (S), the correct combination of the dispersed phase and dispersion medium, respectively is :

(A)

\displaystyle \text{C : liquid in solid; M : liquid in solid; S : solid in gas}

(B)

\displaystyle \text{C : liquid in solid; M : liquid in liquid; S : solid in gas}

(C)

\displaystyle \text{C : solid in liquid; M : liquid in liquid; S : gas in solid}

(D)

\displaystyle \text{C : solid in liquid; M : solid in liquid; S : solid in gas}

Q49Single correctClassification of Elements and Periodicity in Properties

The reaction that does NOT define calcination is:

(A)

\displaystyle \text{Fe}_2\text{O}_3\cdot \text{xH}_2\text{O}\xrightarrow{\Delta}\text{Fe}_2\text{O}_3+\text{xH}_2\text{O}

(B)

\displaystyle 2\text{Cu}_2\,\text{S}+3\text{O}_2\xrightarrow{\Delta}2\text{Cu}_2\text{O}+2\text{SO}_2

(C)

\displaystyle \text{ZnCO}_3\xrightarrow{\Delta}\text{ZnO}+\text{CO}_2

(D)

\displaystyle \text{CaCO}_3\cdot \text{MgCO}_3\xrightarrow{\Delta}\text{CaO}+\text{MgO}+2\text{CO}_2

Q50Single correctd- and f-Block Elements

\text{A}\xrightarrow{4\text{KOH},\text{O}_2}2\,\underset{(\text{Green})}{\text{B}}+2\text{H}_2\text{O}\quad\text{B}\xrightarrow{4\text{HCl}}2\,\underset{(\text{Purple})}{\text{C}}+\text{MnO}_2+2\text{H}_2\text{O}\quad2\text{C}\xrightarrow{\text{H}_2\text{O},\text{KI}}2\,\text{A}+\text{KOH}+\text{D}

In the above sequence of reactions, A and D, respectively, are:

(A)

\displaystyle \text{KI and KMnO}_4

(B)

\displaystyle \text{MnO}_2\text{ and KIO}_3

(C)

\displaystyle \text{KIO}_3\text{ and MnO}_2

(D)

\displaystyle \text{KI and K}_2\text{MnO}_4

Q51Single correctCoordination Compounds

The coordination number of Th in

\text{K}_4\left[\text{Th}(\text{C}_2\text{O}_4)_4(\text{H}_2\text{O})_2\right]

is:

\left(\text{C}_2\text{O}_4^{2-}=\text{oxalato}\right)

(A)

\displaystyle 14

(B)

\displaystyle 6

(C)

\displaystyle 8

(D)

\displaystyle 10

Q52Single correctCoordination Compounds

The number of bridging CO ligand(s) and Co-Co bond(s) in

\text{Co}_2(\text{CO})_8

, respectively are:

(A)

\displaystyle \text{2 and 1}

(B)

\displaystyle \text{2 and 0}

(C)

\displaystyle \text{0 and 2}

(D)

\displaystyle \text{4 and 0}

Q53Single correctHydrocarbons

The major product of the following reaction is:

meta-(but-3-enyl)phenol: benzene with OH and a -CH2CH2CH=CH2 side chain at the meta position; reagents (1) HCl (2) AlCl3 (anhydrous).

(A)

An indane (bicyclic fused benzene and five-membered carbocycle) bearing a methyl group on the carbon of the five-membered ring adjacent to the ring fusion, and a chlorine substituent on the benzene ring at the carbon next to the lower ring-fusion carbon.

(B)

An indane bearing a methyl group on the carbon of the five-membered ring adjacent to the ring fusion (drawn at lower right), and a chlorine substituent on the benzene ring at the position para to the upper ring-fusion carbon.

(C)

An indane bearing a methyl group on the carbon of the five-membered ring adjacent to the ring fusion, and a hydroxyl (HO) substituent on the benzene ring at the carbon next to the lower ring-fusion carbon.

(D)

An indane bearing a methyl group on the carbon of the five-membered ring adjacent to the ring fusion (drawn at lower right), and a hydroxyl (HO) substituent on the benzene ring at the position para to the upper ring-fusion carbon.

Q54Single correctOrganic Compounds Containing Oxygen

The major product obtained in the following conversion is:

Reactant: a benzene ring bearing an acetate ester group (CH3-C(=O)-O-) on one ring carbon and an ortho 1-propenyl (CH=CH-CH3) side chain; reagent over the arrow is Br2 (1 eq.) in MeOH.

(A)

A benzene ring bearing an acetate ester group (CH3-C(=O)-O-) on one ring carbon and, on the ortho carbon, a side chain CH(OMe)-CHBr-CH3 in which the carbon attached to the ring carries a methoxy (OMe) group and the next carbon carries a bromine, ending in a methyl.

(B)

A benzene ring bearing an acetate ester group (CH3-C(=O)-O-) on one ring carbon and, on the ortho carbon, a side chain CHBr-CH(OMe)-CH3 in which the carbon attached to the ring carries a bromine and the next carbon carries a methoxy (OMe) group, ending in a methyl.

(C)

A benzene ring bearing an acetate ester group (CH3-C(=O)-O-) on one ring carbon and, on the para carbon, a bromine substituent, with a propenyl-derived side chain at the ortho position carrying a carbonyl.

(D)

A benzene ring bearing an acetate ester group (CH3-C(=O)-O-) on one ring carbon, a bromine on the ring, and an ortho side chain CH=CH-CH3 bearing an ethyl-related group with a carbonyl.

Q55Single correctOrganic Compounds Containing Oxygen

The major product obtained in the following reaction is:

Reactant: a decalin-type fused bicyclic ring carrying a carboxylic acid (COOH) with an adjacent CH2 vinyl/alkene group and a CH3, plus an NO2 group on the lower ring; reagent over arrow is LiAlH4 (mono).

(A)

A decalin-type fused bicyclic ring system bearing an OH group and a CH3 group on the upper ring, with an NO2 group and an OH on the lower ring carbons.

(B)

A decalin-type fused bicyclic ring system bearing a CH3 group and an OH on the upper ring and an NH2 group with an OH on the lower ring carbons.

(C)

A decalin-type fused bicyclic ring system bearing an OH group on the upper ring and an NH2 group with an OH and a CH3 on the lower ring carbons.

(D)

A decalin-type fused bicyclic ring system bearing an OH and a CH3 group on the upper ring and an NO2 group with an OH on the lower ring carbons.

Q56Single correctBiomolecules

In the following compound,
the favourable site/s for protonation is/are :

A purine (adenine) ring system: a fused imidazole and pyrimidine bicyclic ring. The exocyclic amino group (NH2) on the six-membered ring is labelled (a); the pyrimidine ring nitrogen adjacent to the amino-bearing carbon is labelled (b); the other pyrimidine ring nitrogen at the bottom is labelled (c); the imidazole ring nitrogen with no attached hydrogen (pyridine-type) at the top of the five-membered ring is labelled (d); and the imidazole ring nitrogen bearing a hydrogen (N-H, pyrrole-type) at the bottom of the five-membered ring is labelled (e).

(A)

\displaystyle \text{(a) and (e)}

(B)

\displaystyle \text{(b), (c) and (d)}

(C)

\displaystyle \text{(a) and (d)}

(D)

\displaystyle \text{(a)}

Q57Single correctOrganic Compounds Containing Nitrogen

A compound 'X' on treatment with Br /NaOH, provided

\text{C}_3\text{H}_9\,\text{N}

, which gives positive carbylamine test. Compound X

'

is:

(A)

\displaystyle \text{CH}_3\text{COCH}_2\text{NHCH}_3

(B)

\displaystyle \text{CH}_3\text{CH}_2\text{COCH}_2\text{NH}_2

(C)

\displaystyle \text{CH}_3\text{CH}_2\text{CH}_2\text{CONH}_2

(D)

\displaystyle \text{CH}_3\text{CON}(\text{CH}_3)_2

Q58Single correctBiomolecules

The homopolymer formed from 4-hydroxy-butanoic acids is.

(A)

A bracketed polymer repeat unit -[O-C(CH2)3-O]- with a carbonyl (C=O, shown as O double bonded above the C) on the C adjacent to the oxygen, the chain shown with a trailing subscript n.

(B)

A bracketed polymer repeat unit -[O-C(CH2)2-C]- with two carbonyl groups (each a C=O shown above), and trailing subscript n.

(C)

A bracketed polymer repeat unit -[O-C-(CH2)2-C-O]- with two carbonyl groups (each C=O shown above the respective C), with a leading ellipsis and trailing subscript n.

(D)

A bracketed polymer repeat unit -[C(CH2)3-O]- with one carbonyl group (C=O shown above the C), and trailing subscript n.

Q59Single correctBiomolecules

The correct match between Item I and Item II is:

Item I	Item II
(A). $\text{Allosteric effect}$	(P). $\text{Molecule binding to the active site of enzyme}$
(B). $\text{Competitive inhibitor}$	(Q). $\text{Molecule crucial for communication in the body}$
(C). $\text{Receptor}$	(R). $\text{Molecule binding to a site other than the active site of enzyme}$
(D). $\text{Poison}$	(S). $\text{Molecule binding to the enzyme covalently}$

(A)

\displaystyle \text{(A)}\rightarrow\text{(R); (B)}\rightarrow\text{(P); (C)}\rightarrow\text{(Q); (D)}\rightarrow\text{(S)}

(B)

\displaystyle \text{(A)}\rightarrow\text{(P); (B)}\rightarrow\text{(R); (C)}\rightarrow\text{(Q); (D)}\rightarrow\text{(S)}

(C)

\displaystyle \text{(A)}\rightarrow\text{(R); (B)}\rightarrow\text{(P); (C)}\rightarrow\text{(S); (D)}\rightarrow\text{(Q)}

(D)

\displaystyle \text{(A)}\rightarrow\text{(P); (B)}\rightarrow\text{(R); (C)}\rightarrow\text{(S); (D)}\rightarrow\text{(Q)}

Q60Single correctBiomolecules

The correct match between Item I and Item II is:

Item I	Item II
(A). $\text{Ester test}$	(P). $\text{Tyr}$
(B). $\text{Carbylamine test}$	(Q). $\text{AsP}$
(C). $\text{Phthalein dye test}$	(R). $\text{Ser}$
	(S). $\text{Lys}$

(A)

\displaystyle \text{(A)}\rightarrow\text{(Q, R); (B)}\rightarrow\text{(S); (C)}\rightarrow\text{(P)}

(B)

\displaystyle \text{(A)}\rightarrow\text{(R); (B)}\rightarrow\text{(Q); (C)}\rightarrow\text{(P)}

(C)

\displaystyle \text{(A)}\rightarrow\text{(R); (B)}\rightarrow\text{(S); (C)}\rightarrow\text{(Q)}

(D)

\displaystyle \text{(A)}\rightarrow\text{(Q); (B)}\rightarrow\text{(S); (C)}\rightarrow\text{(R)}

JEE Main 2019 January 11, Shift 2 Question Paper with Solutions

Physics30 questions

Chemistry30 questions

Mathematics30 questions

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