datavorous/entrance-exam-dataset huggingface dataset:
Among the following statements:-
I. PCl5 is trigonal bipyramidal whereas IF5 is square pyramidal.
II. Bond enthalpy of O-H bond in water and ethanol is different.
III. All carbon atoms have same hybridisation in carbon suboxide C3O2.
Find out the correct statements.

Options:
A I & II only
B II & III only
C I & III only
D I, II & III

The correct answer is:
I, II & III

Solution:
I.
II. Bond enthalpy of O-H is different in water and ethanol as ethanol contents electron-donating ethyl group.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
Among the following structures, which will show the most stable enamine formation?

(Where Me is -CH3)

Options:
A
B
C
D

The correct answer is:

Solution:
All these enamines are interconvertible through their resonating structures. So most stable form is ‘C’ due to steric factor. All of these has the equal resonance only differ in their geometrical configuration. The enamine in option C has bulky groups on opposite side of double bond. means they have the minimum repulsion between them.

Topic: Chemistry, Amines, JEE Main, JEE Main 2022 (26 Jun Shift 1)
Among the following substituted silanes the one which will give rise to cross linked silicone polymer on hydrolysis is

Options:
A
$\mathrm{R}_4 \mathrm{Si}$

B
$\mathrm{RSiCl}_3$

C
$\mathrm{R}_2 \mathrm{SiCl}_2$

D
$\mathrm{R}_3 \mathrm{SiCl}$

The correct answer is:
$\mathrm{RSiCl}_3$

Solution:

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main, JEE Main 2008
Among the following surfactant molecules, the surfactant that forms micelles in aqueous solution at the lower CMC at ambient condition is

Options:
A CH3CH215N+CH33Br-
B CH3CH211OSO3-Na+
C CH3CH26COO-Na+
D CH3CH211N+CH33Br-

The correct answer is:
CH3CH215N+CH33Br-

Solution:
More is the hydrophobic character in surfactant molecule, lesser is CMC in aqueous solution.
Hydrophobic character ∝ length of carbon chain

Topic: Chemistry, Surface Chemistry, JEE Main
Among the following, the aromatic compounds are :

Choose the correct answer from the following options :

Options:
A (A) and (B) only
B (B) and (C) only
C (B),(C) and (D) only
D (A),(B) and (C) only

The correct answer is:
(B) and (C) only

Solution:
Aromatic compounds are considered as the compound which contains a conjugated planar ring system with delocalized pi-electrons cloud located at alternate double bond and single bond. For a compound to be aromatic it should follow Huckel’s rule which says that the compound should satisfy 4n+2π electrons.

For Aromaticity, full conjugation of (4n+2)π electrons should be there in closed ring.

(A) Non-Aromatic

(B) Aromatic

(C) Aromatic

(D) Anti-Aromatic

Topic: Chemistry, General Organic Chemistry, JEE Main, JEE Main 2021 (16 Mar Shift 1)
Among the following, the coloured compound is

Options:
A
$\mathrm{CuCl}$

B
$\mathrm{K}_3\left[\mathrm{Cu}(\mathrm{CN})_4\right]$

C
$\mathrm{CuF}_2$

D
$\left[\mathrm{Cu}\left(\mathrm{CH}_3 \mathrm{CN}_4\right)\right] \mathrm{BF}_4$

The correct answer is:
$\mathrm{CuF}_2$

Solution:
In $\mathrm{CuF}_2, \mathrm{Cu}^{2+}$ ions exist, having $d^9$-configuration. Unpaired electron causes colour ( $d-d$ transition)
In the crystalline form, $\mathrm{CuF}_2$ is blue coloured

Topic: Chemistry, Coordination Compounds, JEE Main
Among the following the compound that is both paramagnetic and coloured is

Options:
A $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$
B $\left(\mathrm{NH}_{4}\right)_{2}\left[\mathrm{TiCl}_{6}\right]$
C $\mathrm{VOSO}_{4}$
D $\mathrm{K}_{3} \mathrm{Cu}(\mathrm{CN})_{4}$

The correct answer is:
$\mathrm{VOSO}_{4}$

Solution:
(d) $\operatorname{In} \mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right] \mathrm{Cu}$ is in $+1$ oxidation state hence has no unpaired electron hence colourless and diamagnetic.
(b) $\mathrm{In}\left(\mathrm{NH}_{4}\right)_{2}\left[\mathrm{TiCl}_{6}\right] \mathrm{Ti}$ is in $+4$ oxidation state. hence has no unpaired electron hence colourless and diamagnetic.
(c) $\operatorname{In} \operatorname{VOSO}_{4}, V$ is in $+4$ oxidation state hence has one unpaired electron, thus it is coloured and paramagnetic.
(a) $\operatorname{In} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$, Cr is in $+6$ oxidation. hence has no unpaired electron and thus it is diamagnetic. Though $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ has no unpaired electron but it is coloured. This is due to charge transfer spectrum.

Topic: Chemistry, d and f Block Elements, JEE Main
Among the following.
the compounds which can exhibit optical. activity are :

Options:
A only II, IV and V
B only IV and V
C only I, II and V
D only I, II and IV

The correct answer is:
only II, IV and V

Solution:
(I)
C.O.S. is present so inactive

(II)
C.O.S.→X
P.O.S. →X
A.A.O.S.→X
so active

(III) P.O.S. is present so inactive

(IV) C.O.S. and P.O.S. both are not present so active

(V) C.O.S. and P.O.S. both are not present so active

Topic: Chemistry, General Organic Chemistry, JEE Main
Among the following the correct statement is

Options:
A Internal energy of a gas depends only on the state of the gas.
B In an isothermal process change in internal energy is maximum.
C Area under pressure, volume graph equals heat supplied in any process.
D Work done is state dependent but not path dependent.

The correct answer is:
Internal energy of a gas depends only on the state of the gas.

Solution:
Internal energy of a gas is state dependent but path independent.
In an isothermal process, temperature remains constant, therefore change in internal energy is zero. Area under pressure, volume graph is equal to the work done by the gas. Work done is both state and path dependent.

Topic: Physics, Thermodynamics, NEET
Among the following, the correct statement is:

Options:
A sols of metal sulphides are lyophilic.
B Brownian movement is more pronounced for smaller particles than for bigger-particles.
C one would expect charcoal to adsorb chlorine more than hydrogen sulphide.
D Hardy Schulze law states that bigger the size of the ions, the greater is its coagulating power.

The correct answer is:
Brownian movement is more pronounced for smaller particles than for bigger-particles.

Solution:
Brownian movement is the random motion of particles suspended in a fluid (liquid or gas), resulting from their collision with the fast moving atom or molecules in the liquid or gaseous state of the matter. That means, smaller particles are responsible for the Brownian movement.

Topic: Chemistry, Surface Chemistry, JEE Main, JEE Main 2017 (08 Apr Online)
Among the following, the correctly matched pair is

Options:
A electron deficient hydride $-\mathrm{SiH}_4$
B saline hydride - $\mathrm{CrH}$
C electron precise hydride - HF
D electron rich hydride $-\mathrm{NH}_3$

The correct answer is:
electron rich hydride $-\mathrm{NH}_3$

Solution:
$\mathrm{NH}_3$ is an electron-rich hydride as $\mathrm{N}$-atom belongs to group - 15 and uses three of its valence electrons to make three $\mathrm{N}-\mathrm{H}$ bonds and the remaining two electrons form a lone pair.

Topic: Chemistry, Hydrogen, AP EAMCET, AP EAMCET 2023 (15 May Shift 2)
Among the following, the energy of 2s orbital is lowest in:

Options:
A K
B H
C Na
D Li

The correct answer is:
K

Solution:
Potassium will have the least energy in its 2s orbital. This is due to the fact that the 2s orbital is closest to the nucleus in potassium because of its greater nuclear charge.

Topic: Chemistry, Structure of Atom, JEE Main, JEE Main 2019 (12 Apr Shift 2)
Among the following, the essential amino acid is:

Options:
A Valine
B Alanine
C Serine
D Aspartic acid

The correct answer is:
Valine

Solution:
Valine is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group, an α-carboxylic acid group, and a side chain isopropyl group, making it a non-polar aliphatic amino acid

Topic: Chemistry, Biomolecules, JEE Main, JEE Main 2017 (08 Apr Online)
Among the following, the false statement is:

Options:
A Latex is a colloidal solution of rubber particles which are positively charged
B Tyndall effect can be used to distinguish between a colloidal solution and a true solution.
C It is possible to cause artificial rain by throwing electrified sand carrying charge opposite to the one on clouds from an aeroplane.
D Lyophilic sols can be coagulated by adding an electrolyte.

The correct answer is:
Latex is a colloidal solution of rubber particles which are positively charged

Solution:
Latex is a colloidal solution of rubber particles which are negatively charged not positively charged.

Topic: Chemistry, Surface Chemistry, JEE Main, JEE Main 2019 (12 Jan Shift 2)
Among the following, the group of molecules that undergoes rapid hydrolysis is

Options:
A SF6,Al2Cl6,SiMe4
B BCl3,SF6,SiCl4
C BCl3,SiCl4,PCl5
D SF6,Al2Cl6,SiCl4

The correct answer is:
BCl3,SiCl4,PCl5

Solution:
BCl3,SiCl4 and PCl5 get radily hydrolysed to give orthoboric, orthosilicic and phosphoric acid respectively.
BCl3+3H2O→H3BO3+3HCl
SiCl4+4H2O→H4SiO4+4HCl
PCl5+H2O→POCl3+2HCl→H2OexcessH3PO4+HCl

Topic: Chemistry, s Block Elements, JEE Main
Among the following, the incorrect statement about colloids is:

Options:
A They are larger than small molecules and have high molar mass.
B They can scatter lighht.
C The osmotic pressure of a collodial solution is of higher order than the true solution at the same concentration.
D The range of diameters of colloidal particles is between 1 and 1000 nm.

The correct answer is:
The osmotic pressure of a collodial solution is of higher order than the true solution at the same concentration.

Solution:
Due to the bigger size of colloidal particles the number of particles in a colloidal solution is comparatively small as compared to a true solution. Hence the values of colligative properties are of small order as compared to values shown by true solutions at same concentration.

Topic: Chemistry, Surface Chemistry, JEE Main, JEE Main 2019 (12 Apr Shift 2)
Among the following the incorrect statement is

Options:
A
Density of crystals remains unaffected due to Frenkel defect.

B
In BCC unit cell the void space is $32 \%$.

C
Density of crystals decreases due to Schottky defect.

D
Electrical conductivity of semiconductors and metals increases with increase in temperature.

The correct answer is:
Electrical conductivity of semiconductors and metals increases with increase in temperature.

Solution:
The electrical resistance of metals depends upon temperature. Electrical resistance decreases with decrease in temperature and becomes zero near the absolute temperature. Material in this state is said to possess super conductivity.

Topic: Chemistry, Solid State, JEE Main, JEE Main 2012 (26 May Online)
Among the following, the incorrect statement is:

Options:
A at low pressure, real gases show ideal behaviour.
B at very low temperature, real gases show ideal behaviour.
C at Boyle's temperature, real gases show ideal behaviour.
D at very large volume, real gases show ideal behaviour.

The correct answer is:
at very low temperature, real gases show ideal behaviour.

Solution:
A real gas behaves like ideal gas at high temperature and low pressure. At very low temperature intermolecular forces of attraction will be quite significant as molecular randomness is very low due to which at very low temperature real gases can't show ideal behaviour.

Topic: Chemistry, States of Matter, JEE Main, JEE Main 2017 (08 Apr Online)
Among the following, the incorrect statement is

Options:
A cellulose and amylose has 1,4-glycosidic linkage.
B lactose contains β-D-galactose and β-D-glucose.
C maltose and lactose has 1,4-glycosidic linkage.
D sucrose and amylose has 1,2-glycosidic linkage.

The correct answer is:
sucrose and amylose has 1,2-glycosidic linkage.

Solution:
In amylose, 1,4-glycosidic linkage is present.
So, this option statement is incorrect.

Sucrose has 1,2-glycosidic linkage between glucose and fructose.

cellulose and amylose has 1,4-glycosidic linkage. lactose contains β-D-galactose and β-D-glucose. maltose and lactose has 1,4-glycosidic linkage.

Topic: Chemistry, Biomolecules, JEE Main, JEE Main 2018 (16 Apr Online)
Among the following the incorrect statement is

Options:
A Density of crystals remains unaffected due to Frenkel defect.
B In BCC unit cell the void space is $32 \%$.
C Density of crystals decreases due to Schottky defect.
D Electrical conductivity of semiconductors and metals increases with increase in temperature.

The correct answer is:
Electrical conductivity of semiconductors and metals increases with increase in temperature.

Solution:
The electrical resistance of metals depends upon temperature. Electrical resistance decreases with decrease in temperature and becomes zero near the absolute temperature. Material in this state is said to possess super conductivity.

Topic: Chemistry, Solid State, VITEEE, VITEEE 2016
Among the following, the incorrect statement is

Options:
A cellulose and amylose has 1,4-glycosidic linkage.
B lactose contains β-D-galactose and β-D-glucose.
C maltose and lactose has 1,4-glycosidic linkage.
D sucrose and amylose has 1,2-glycosidic linkage.

The correct answer is:
sucrose and amylose has 1,2-glycosidic linkage.

Solution:
In amylose, 1,4-glycosidic linkage is present.
So, this option statement is incorrect.

Sucrose has 1,2-glycosidic linkage between glucose and fructose.

cellulose and amylose has 1,4-glycosidic linkage. lactose contains β-D-galactose and β-D-glucose. maltose and lactose has 1,4-glycosidic linkage.

Topic: Chemistry, Biomolecules, JEE Main
Among the following, the main reactions occurring in blast furnace during extraction of iron from haematite are:
i. $\mathrm{Fe}_{2} \mathrm{O}_{3}+3 \mathrm{CO} \rightarrow 2 \mathrm{Fe}+3 \mathrm{CO}_{2}$
ii. $\mathrm{FeO}+\mathrm{SiO}_{2} \rightarrow \mathrm{FeSiO}_{3}$
iii. $\mathrm{Fe}_{2} \mathrm{O}_{3}+3 \mathrm{C} \rightarrow 2 \mathrm{Fe}+3 \mathrm{CO}$
iv. $\mathrm{CaO}+\mathrm{SiO}_{2} \rightarrow \mathrm{CaSiO}_{3}$

Options:
A ii and ii
B i and iv
C \( \mathrm{i} \) and \( \mathrm{ii} \)
D iiii and iv

The correct answer is:
i and iv

Solution:
(B)

Topic: Chemistry, General Principles and Processes of Isolation of Metals, KCET, KCET 2019
Among the following the maximum covalent character is shown by the compound:

Options:
A
$\mathrm{SnCl}_2$

B
$\mathrm{AlCl}_3$

C
$\mathrm{MgCl}_2$

D
$\mathrm{FeCl}_2$

The correct answer is:
$\mathrm{AlCl}_3$

Solution:
Greater charge and small size of cation cause more polarization and more covalent is that compound

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
Among the following the maximum covalent character is shown by the compound:

Options:
A
$\mathrm{SnCl}_2$

B
$\mathrm{AlCl}_3$

C
$\mathrm{MgCl}_2$

D
$\mathrm{FeCl}_2$

The correct answer is:
$\mathrm{AlCl}_3$

Solution:
Greater charge and small size of cation cause more polarization and more covalent is that compound

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main, JEE Main 2011
Among the following the molecule with the highest dipole moment is

Options:
A CH 3 Cl
B CH 2 Cl 2
C CHCl 3
D CCl 4

The correct answer is:
CH 3 Cl

Solution:
For polar molecule dipole moment, μ depends upon geometry. Symmetrical molecule is non-polar even through it contains polar bonds. Bond dipole moment of C−H and C−Cl bond reinforce on one another.
In CHCl 3 the resultant C−H and C−Cl dipoles oppose the resultant of two C−Cl dipoles, while in CH 2 Cl 2 the resultant of C−H dipoles add to resultant of two C−Cl. In case of CH 3 Cl the resultant of two C−H dipoles add to the resultant of C−H and C−Cl dipoles. Thus dipole moment of CH 3 Cl is highest among the given compounds. CCl 4 becomes symmetrical and its reduces to zero.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
Among the following, the molecule with the lowest dipole moment is

Options:
A
$\mathrm{CHCl}_3$

B
$\mathrm{CH}_3 \mathrm{Cl}$

C
$\mathrm{CH}_2 \mathrm{Cl}_2$

D
$\mathrm{CCl}_4$

The correct answer is:
$\mathrm{CCl}_4$

Solution:
$\mathrm{CCl}_4$ has lowest (zero) dipole moment. This is due to its symmetrical tetrahedral structure. Due to which dipole moment of one bond is cancelled by opposite dipole moment of the other three bonds.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main, JEE Main 2012 (19 May Online)
Among the following, the narrow spectrum antibiotic is:

Options:
A Penicillin-G
B Ampicillin
C Amoxycillin
D Chloramphenicol

The correct answer is:
Penicillin-G

Solution:
Those effective mainly against gram positive or gram negative bacteria are narrow spectrum antibiotics.
Pencillin-G has a narrow spectrum.

Topic: Chemistry, Chemistry in Everyday Life, NEET, NEET 2019 (All India)
Among the following, the narrow spectrum antibiotic is:

Options:
A Penicillin-G
B Ampicillin
C Amoxycillin
D Chloramphenicol

The correct answer is:
Penicillin-G

Solution:
Those effective mainly against gram positive or gram negative bacteria are narrow spectrum antibiotics.
Pencillin-G has a narrow spectrum.

Topic: Chemistry, Chemistry in Everyday Life, NEET
Among the following, the number of aromatic compounds are

Options:
A 3
B 4
C 5
D 6

The correct answer is:
5

Solution:
Here following 5 compounds are aromatic as they full fill the condition to show aromaticity
is non-aromatic as it non-planar as have 2  sp 3 hybridised carbon atoms.

Topic: Chemistry, General Organic Chemistry, JEE Main
Among the following, the number of aromatic compound(s) is

Options:

The correct answer is:
5

Solution:
-

Topic: Chemistry, General Organic Chemistry, JEE Main
Among the following, the number of compounds than can react with PCl5 to give POCl3 are O2,CO2,SO2,H2O,H2SO4,P4O10

Options:

The correct answer is:
4

Solution:
PCl5 on reaction with these 4 compounds gives POCl3
PCl5+SO2→POCl3+SOCl2
PCl5+H2O→POCl3+2HCl
PCl5+H2SO4→SO2Cl2+2POCl3+2HCl
6PCl5+P4O10→10POCl3

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Among the following the number of compounds which will give positive iodoform reaction is _____.

(a) 1-Phenylbutan-2-one

(b) 2-Methylbutan-2-ol

(c) 3-Methylbutan-2-ol

(d) 1-Phenylethanol

(e) 3, 3-dimethylbutan-2-one

(f) 1-Phenylpropan-2-ol

Options:

The correct answer is:
4

Solution:
Iodoform test is used to check the presence of carbonyl compounds with the structure R-CO-CH3 or alcohols with the structure R-CH(OH)-CH3 in a given unknown substance. The reaction of iodine, a base and a methyl ketone gives a yellow precipitate along with an “antiseptic” smell.

Hence, (c), (d), (e) and (f) give iodoform reaction

Topic: Chemistry, Aldehydes and Ketones, JEE Main, JEE Main 2023 (06 Apr Shift 2)
Among the following, the number of halide(s) which is/ are inert to hydrolysis is

(A) BF3
(B) SiCl4
(C) PCl5
(D) SF6

Options:

The correct answer is:
1

Solution:
SF6 is inert towards hydrolysis
∴ answere is 1

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main, JEE Main 2021 (25 Feb Shift 1)
Among the following, the number of reaction(s) that produce(s) benzaldehyde is

Options:
A I, II
B I, III
C II, III, IV
D I, II, III and IV

The correct answer is:
I, II, III and IV

Solution:
All these reactions can be used to prepare benzaldehyde as follows

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Among the following the number of state variable is

Internal energy U

Volume V

Heat q

Enthalpy H

Options:

The correct answer is:
3

Solution:
A property whose value doesn't depend on the path taken to reach that specific value is known to as state functions or point functions. State functions are the values which depend on the state of the substance like temperature, pressure or the amount or type of the substance, as a matter of fact, state functions do not depend on how the state was reached or established.

Among the given functions Internal energy, enthalpy, volume, are the state functions.

The state of a thermodynamic system is described by its macroscopic properties.

Topic: Chemistry, Thermodynamics (C), JEE Main, JEE Main 2022 (28 Jul Shift 2)
Among the following the one that gives positive iodoform test upon reaction with $\mathrm{I}_2$ and $\mathrm{NaOH}$ is

Options:
A
$\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_2 \mathrm{CH}_3$

B
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{OH}$

C

D
$\mathrm{PhCHOHCH}_3$

The correct answer is:
$\mathrm{PhCHOHCH}_3$

Solution:
No Solution Available

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main, JEE Main 2006
Among the following the one that gives positive iodoform test upon reaction with I2 and NaOH is

Options:
A CH3CH2CH(OH)CH2CH3
B C6H5CH2CH2OH
C PhCHOHCH3
D CH3CH(CH2OH)CH3

The correct answer is:
PhCHOHCH3

Solution:
Iodoform test is given by only the compounds containing CH3CO - or CH3CHOH - group. Ph CH OH CH 3 + 4 I 2 + 6 NaOH ⟶ Δ CHI 3 + PhCOONa + 5 NaI + 5 H 2 O

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Among the following, the one that is not a greenhouse gas is:

Options:
A nitrous oxide
B methane
C ozone
D sulphur dioxide

The correct answer is:
sulphur dioxide

Solution:
Earth's greenhouse gases trap heat in the atmosphere and warm the planet. The main gases responsible for the greenhouse effect include carbon dioxide, methane, nitrous oxide, and water vapour (which all occur naturally), and fluorinated gases like CFCs (which are synthetic).

Sulphur dioxide does not absorb and trap infrared radiation, but it is considered an indirect greenhouse gas because when coupled with elemental carbon, it forms aerosols. Hence, sulphur dioxide is not a greenhouse gas.

Topic: Chemistry, Environmental Chemistry, NEET, NEET 2019 (All India)
Among the following, the optically inactive compound is

Options:
A

B
C
D

The correct answer is:

Solution:
are non-separable mirror images, that's why this compound is optically active.
Phosphorus is attached with bulky groups, so the oscillation becomes zero and it can show optical activity.
Compound D has one chiral carbon atom and thus, is optically active.

Topic: Chemistry, General Organic Chemistry, JEE Main
Among the following the order of reactivity towards nucleophilic addition is

Options:
A
$\mathrm{CH}_3 \mathrm{CHO}>\mathrm{CH}_3 \mathrm{COCH}_3>\mathrm{HCHO}$

B
$\mathrm{HCHO}>\mathrm{CH}_3 \mathrm{CHO}>\mathrm{CH}_3 \mathrm{COCH}_3$

C
$\mathrm{CH}_3 \mathrm{CHO}>\mathrm{HCHO}>\mathrm{CH}_3 \mathrm{COCH}_3$

D
$\mathrm{CH}_3 \mathrm{COCH}_3>\mathrm{CH}_3 \mathrm{CHO}>\mathrm{HCHO}$

The correct answer is:
$\mathrm{HCHO}>\mathrm{CH}_3 \mathrm{CHO}>\mathrm{CH}_3 \mathrm{COCH}_3$

Solution:
Presence of alkyl group in carbonyl compounds decreases their reactivity towards nucleophilic addition. Further greater the number of such groups lesser will be the reactivity towards nucleophilic addition $\therefore$ correct order is

Topic: Chemistry, General Organic Chemistry, JEE Main, JEE Main 2012 (07 May Online)
Among the following, the plot that correctly represents the conductometric titration of 0.05 M H2SO4 with 0.1 M NH4OH is

Options:
A
B
C
D

The correct answer is:

Solution:
The principle of conductometric titration is based on the fact that during the titration one of the ions is replaced by other and invariably these two ions differ in the ionic conductivity.

In the conductometric titration of 0.05 M H2SO4 with 0.1 M NH4OH, initially the fast moving H+ ion get neutralised as H2O and is replaced by slow moving NH4+ ion up to neutralisation point. After neutralisation point, weak electrolyte NH4OH is added gradually, which do not affect the conductance.

Topic: Chemistry, Electrochemistry, JEE Main
Among the following, the reaction that is accompanied by a decrease in the entropy is

Options:
A N2g+3H2g→2NH3g
B C6H12O6s+6O2g→6CO2g+6H2Ol
C PCl5s→PCl3l+Cl2g
D 2H2Ol→2H2g+O2g

The correct answer is:
N2g+3H2g→2NH3g

Solution:
Entropy is the measure of randomness. As the randomness (disorder) increases, entropy increases,
The order of entropy is
Solid(particlesorderlyarranged)<Liquid<Gas(mostdisordered)
Thus, in reaction
N2g+3H2g→2NH3g
Entropy decreases because number of gaseous molecules decreases.

Topic: Chemistry, Thermodynamics (C), JEE Main