datavorous/entrance-exam-dataset huggingface dataset:
Among the following the paramagnetic compound is

Options:
A O3
B N2O
C Na2O2
D KO2

The correct answer is:
KO2

Solution:
Na2O2 or O22-=σ1s2σ*1s2,σ2s2σ*2s2,σ2pZ2,π2pX2=π2pY2,π*2pX2=π*2pY2
Number of unpaired electrons = 0
N=N→O number of unpaired electrons =0
O=O⊕–O-↔O=O→O
Number of unpaired electrons =0
KO2 or O2-=σ1s2,σ*1s2σ2s2,σ*2s2,σ2pZ2,π2pX2=π2pY2,π*2pX2=π*2pY1
Number of unpaired electrons =1
So O2- is paramagnetic.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
Among the following, the paramagnetic compound is:

Options:
A Na2O2
B O3
C N2O
D O 2 −

The correct answer is:
O 2 −

Solution:
Odd number electron generally indicates paramagnetic nature and even number of electron diamagnetic nature

O 2 2â â18 Electron diamagnetic.
O 3 â24 Electron diamagnetic.
N 2 O â22 Electron diamagnetic.
O 2 â â17 Electrons one unpaired electron paramagnetic.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
Among the following, the reaction that proceeds through an electrophilic substitution, is:

Options:
A
B
C
D

The correct answer is:

Solution:
Option B proceeds through an electrophilic substitution reaction.

Cl2 reacts with AlCl3 to form Cl+ and AlCl4-. This Cl+ attaches the molecule making it electrophilic substitution.

Option A is nucleophilic addition.

Option C is an addition reaction.

Option D is nucleophilic substitution.

Topic: Chemistry, Haloalkanes and Haloarenes, NEET, NEET 2019 (All India)
Among the following, the set of critical elements are:

Options:
A Na, K and Ca
B N, P and Mg
C N, P and K
D Mn, B and Mo

The correct answer is:
N, P and K

Solution:
Nitrogen, phosphorous and potassium are important elements which are very much necessary for normal growth and development of the plants.

Topic: Biology, Mineral Nutrition, NEET
Among the following, the surfacant that will form micelles in aqueous solution at the lowest molar concentration at ambient condition is:

Options:
A CH 3 CH 2 15 N + CH 3 3 Br −
B CH 3 CH 2 11 OSO 3 −   Na +
C CH 3 CH 2 6 COO − Na +
D CH 3 CH 2 11 N + CH 3 3 Br −

The correct answer is:
CH 3 CH 2 15 N + CH 3 3 Br −

Solution:
Larger the hydrophobic fragment of surfactant molecule easier will be micellisation, smaller the CMC value i.e. CH 3 CH 2 15 N + CH 3 3 Br − will have lowest CMC due to longest hydrophobic chain.

Topic: Chemistry, Surface Chemistry, NEET
Among the following, the third ionization energy is highest for

Options:
A Aluminium
B Beryllium
C Boron
D Magnesium

The correct answer is:
Beryllium

Solution:
Beryllium has highest third ionization energy as Be2+ has 1s2 (He gas configuration) so removal of electron is very tough.
Be→I1Be+→I2Be2+→I3
I1<I2<<<I3

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Among the following transition elements, which one has the highest second ionisation energy?

(i) V Z=23 (ii) Cr Z=24 (iii) Mn Z=25 (iv) Ti Z=22

Options:
A (i)
B (ii)
C (iii)
D (iv)

The correct answer is:
(ii)

Solution:
The general trend observed in the second ionisation enthalpy of 3d-series elements is that as we move from left to right in the period, the ionisation energy increases. But, Cr and Zn are exceptions to this trend. The value of second ionisation energy for Cr is more than Mn. This can be explained based on the electronic configuration of their M+ ions:

Cr+24=Ar3d5 and Mn+25=Ar3d54s1

Cr+ has a stable electronic configuration because of half-filled d-subshell. Thus removing an electron from it is difficult. Therefore, Cr has the highest second ionisation energy among the given elements.

The correct order for second ionisation energy for the given elements is Ti<V<Mn<Cr.

Topic: Chemistry, d and f Block Elements, NEET
Among the following, where do you think the process of decomposition would be the fastest?

Options:
A Tropical rain forest
B Antarctic
C Dry arid region
D Alpine region

The correct answer is:
Tropical rain forest

Solution:
Warm and moist environment favour decomposition. Decomposition is largely an oxygen requiring process. Low temperature and anaerobiosis inhibit decomposition resulting in build up of organic materials. The process of decomposition would be the fastest is tropical rain forest.

Topic: Biology, Ecosystem, NEET
Among the following, which are ambidentate ligands?
(i) SCN-
(ii) NO3-
(iii) NO2-
(iv) C2O42-

Options:
A (i) and (iii)
B (i) and (iv)
C (ii) and (iii)
D (ii) and (iv)

The correct answer is:
(i) and (iii)

Solution:
SCN- and NO2- are ambidentate ligands since they have more than one donor atoms to attach to the central metal atom.

Topic: Chemistry, Coordination Compounds, NEET
Among the following, which compound is likely to have the highest boiling point?

Options:
A Benzene
B Toluene
C Phenol
D Cyclohexane

The correct answer is:
Phenol

Solution:
Phenol's ability to form hydrogen bonds gives it a higher boiling point compared to the other compounds listed.

Topic: Chemistry, Alcohols Phenols and Ethers, NEET
Among the following which is not the $\pi$-bonded organometallic compound?

Options:
A $\mathrm{K}\left[\mathrm{PtCl}_3\left(\eta^2-\mathrm{C}_2 \mathrm{H}_4\right)\right]$
B $\mathrm{Fe}\left(\eta^5-\mathrm{C}_2 \mathrm{H}_5\right)_2$
C $\mathrm{Cr}\left(\eta^6-\mathrm{C}_6 \mathrm{H}_6\right)_2$
D $\left(\mathrm{CH}_3\right)_4 \mathrm{Sn}$

The correct answer is:
$\left(\mathrm{CH}_3\right)_4 \mathrm{Sn}$

Solution:
$\left(\mathrm{CH}_3\right)_4 \mathrm{Sn} \text { is a sigma bonded }$

Related Theory
The bond between the metal atom and the carbon belonging to the organic compound is covalent in nature. When metals with relatively high electropositivity (such as sodium and lithium) form organo-metallic compounds, a carbanionic nature is exhibited by the carbon which is bound to the central metal atom.

Topic: Chemistry, Coordination Compounds, NEET, NEET 2003
Among the following which is not the pi-bonded organometallic compound?

Options:
A K[PtCl3(η2-C2H4)]
B Fe(η5-C5H5)2
C Cr(η6-C6H6)2
D (CH3)4Sn

The correct answer is:
(CH3)4Sn

Solution:
In case of (CH3)4Sn only sigma bonds are possible and there is no pi electron density so it is sigma bond complex.

Topic: Chemistry, Coordination Compounds, NEET
Among the following, which is the strongest Lewis acid?

Options:
A BF3
B BCl3
C BBr3
D BI3

The correct answer is:
BI3

Solution:
The strengths of boron halides as Lewis acids are in the order BI 3 > BBr 3 > BCl 3 > BF 3 . This order is the opposite of what is expected on steric grounds as well as from considerations of electronegatively. It can be explained in terms of boron-halogen-bonding.
Here, acidic nature â1extent of backbonding

Topic: Chemistry, Ionic Equilibrium, NEET
Among the following which is the strongest oxidising agent?

Options:
A $\mathrm{F}_2$
B $\mathrm{Br}_2$
C $\mathrm{I}_2$
D $\mathrm{Cl}_2$

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

Solution:
Key Idea Element having higher tendency to get reduced or to accept an electron, is strong oxidising agent.
Fluorine is the most electronegative element because electronegativity decreases on moving down the group. Hence, it gets reduced readily into $\mathrm{F}^{-}$ion and is a strongest oxidising agent.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET, NEET 2009 (Screening)
Among the following, which one is a wrong statement?

Options:
A PH5 and BiCl5 do not exist.
B pπ-dπ bonds are present in SO2.
C SeF4 and CH4 have the same shape.
D I3+ has a bent geometry.

The correct answer is:
SeF4 and CH4 have the same shape.

Solution:
The shape of SeF4 would be see-sawed, whereas that of CH4 would be tetrahedral.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET, NEET 2016 (Phase 2)
Among the following, which one is a wrong statement?

Options:
A PH5 and BiCl5 do not exist
B pπ-dπ bonds are present in SO2
C SeF4 and CH4 have same shape
D I3+ has bent shape

The correct answer is:
SeF4 and CH4 have same shape

Solution:

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
Among the following, which vitamin can be synthesized by bacteria in the human gut?

Options:
A Vitamin A
B Vitamin C
C Vitamin D
D Vitamin K

The correct answer is:
Vitamin K

Solution:
Some bacteria in the human gut can synthesize Vitamin K, which is why it is also known as the "gut bacteria vitamin."

Topic: Chemistry, Biomolecules, NEET
Among the given alkaline earth metal ions, which one is the largest in size?

Options:
A Be2+
B Mg2+
C Sr2+
D Ba2+

The correct answer is:
Ba2+

Solution:
As you move down the alkaline earth metal group, the ionic size increases. Among the options provided, Ba2+ is the largest ion.

Topic: Chemistry, s Block Elements, NEET
Among the given compounds, the most susceptible to nucleophilic attack at the carbonyl group is

Options:
A $\mathrm{CH}_3 \mathrm{COOCH}_3$
B $\mathrm{CH}_3 \mathrm{CONH}_2$
C $\mathrm{CH}_3 \mathrm{COOCOCH}_3$
D $\mathrm{CH}_3 \mathrm{COCl}$

The correct answer is:
$\mathrm{CH}_3 \mathrm{COCl}$

Solution:
Key Idea Lesser the electron density of acyl carbon atom, more will be the susceptibility of nucleophile to attack it.
The $\mathrm{Cl}$ atom has strong $-I$ effect and weakest $+\mathrm{R}$ effect because of the weak $\pi$-bond between the small sized $\mathrm{C}$-atom and large sized $\mathrm{Cl}$ atom. Thus, in $\mathrm{CH}_3 \mathrm{COCl}$, acyl carbon has least electron density and hence, more susceptible for nucleophilic attack.

Topic: Chemistry, Aldehydes and Ketones, NEET, NEET 2010 (Screening)
Among the given names of hormones, how many of them show a physiological response by changing the gene expression after binding with DNA inside the target cells?

Oxytocin, Prolactin, Thyroxine, Calcitonin, Vasopressin, Estrogen, FSH, Cortisol, Testosterone, Adrenaline, Aldosterone

Options:
A Three
B Five
C Seven
D Nine

The correct answer is:
Five

Solution:
Lipid-soluble hormones enter inside the target cells and binds to their specific intracellular receptors to form H-R complex. This complex finally moves and binds to DNA inside the nucleus causes change in gene expression to give a physiological response. From the given list, five (estrogen, cortisol, aldosterone, testosterone and thyroxine) are steroid or lipid-soluble hormones.

Topic: Biology, Chemical Coordination and Integration, NEET
Among the given options find out a group of correct features about floral characters of the family Liliaceae.

Options:
A Tetrametous actinomorphic, polyphyllous unilocular ovary, axile placentation
B Trimerous, actinormorphic, polyandrous superior ovay axile placentation
C Six tapals, zygomorphic, six stamens, bilocular ovary, axile placentation
D Bisexual, zygomorphic, gamophyllous inferior ovary marginal placentation

The correct answer is:
Trimerous, actinormorphic, polyandrous superior ovay axile placentation

Solution:
Angiosperms plants are divided into two categories as monocots and dicots. Monocots have trimerous flowers while dicots have tetramerous or pentamerous flowers. Flowers of this family are actinomorphic (radial symmetry), polyandrous (several stamens), superior ovary (hypogynous), and with axile placentation (ovules in the multilocular ovary), etc.

Topic: Biology, Morphology of Flowering Plants, NEET
Among the given options, this compound will exhibit:

Options:
A Geometrical isomerism
B Optical isomerism
C Geometrical and optical isomerism
D Tautomerism

The correct answer is:
Optical isomerism

Solution:
The restricted rotation of atoms or groups around the doubly bonded carbon atoms gives rise to different geometries of such compounds. The stereoisomers of this type are called geometrical isomers.

In alkenes, among the double-bonded carbon atoms, if any of the carbon atoms is attached to two similar types of groups through its other two single bonds, it can not show geometrical isomerism. Since the given compound has two methyl groups attached to the same carbon (as shown below), it can not show geometrical isomerism.

An asymmetric carbon atom is the one which is attached to four different groups through all its four valencies. If the compound contains one asymmetric carbon, it is said to be chiral and will show optical isomerism. The given compound has one asymmetric carbon (as shown below) and thus will show optical isomerism.

Topic: Chemistry, General Organic Chemistry, NEET
Among the given plant groups, the highest number of species diversity in the world is represented by?

Options:
A Lichen
B Pteridophyte
C Algae
D Angiosperm

The correct answer is:
Angiosperm

Solution:
The highest number of species diversity in the world is represented by Angiosperms. Flowering plants has maximum species diversity with 1.5 lakh species, this is followed by Algae, pteridophyta and minimum number of Lichens.

Topic: Biology, Plant Kingdom, NEET
Among the given species the one which contains weakest carbon- oxygen bond : CO 2 ,  CH 3 COO − , CO,  CO 3 2−

Options:
A CO2
B CH3COO-
C CO
D CO32-

The correct answer is:
CO32-

Solution:
Bond strength ∝ Bond order
Bond order is determined through resonating structure. Among the given species, the bond dissociation energy of C-O bond is minimum in case of CO32- by which C-O bond become more weaker in CO32- or the bond order of CO32- (1.33) is minimum so the bond become weaker.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
Among the Group 15 elements, which elements form predominantly basic oxides?

Options:
A Nitrogen
B Arsenic
C Antimony
D Bismuth

The correct answer is:
Bismuth

Solution:
The paragraph states that the oxides of bismuth are predominantly basic.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Among the Group 15 elements, which oxides are predominantly basic?

Options:
A Nitrogen and phosphorus
B Arsenic and antimony
C Bismuth
D All of them are predominantly basic

The correct answer is:
Bismuth

Solution:
The paragraph mentions that the oxides of bismuth are predominantly basic.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Among the group XIV elements, namely Sn, C, Si, and Ge, their conductive properties differ. Which of the following statements explains this phenomenon?

Options:
A Sn has a completely filled valence band due to its larger atomic size.
B C possesses a large energy gap of 5.4 eV, making it an insulator.
C Si's energy gap of 1.1 eV places it in the category of a semiconductor.
D Ge's energy gap of 0.7 eV allows it to exhibit semiconductor behavior.

The correct answer is:
C possesses a large energy gap of 5.4 eV, making it an insulator.

Solution:
Correct Option is : (B)
C possesses a large energy gap of 5.4 eV, making it an insulator.

Topic: Chemistry, Semiconductors, NEET
Among the halogens, which halogen forms two stable oxides, OF2 and O2F2?

Options:
A Fluorine
B Chlorine
C Bromine
D Iodine

The correct answer is:
Fluorine

Solution:
Fluorine forms two stable oxides, OF2 and O2F2.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Among the halogens, which halogen oxide is thermally stable at 298 K?

Options:
A Cl2O
B Br2O
C OF2
D I2O4

The correct answer is:
OF2

Solution:
OF2 is thermally stable at 298 K.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Among the human ancestors the brain size was more than $1000 \mathrm{cc}$ in:

Options:
A Homo erectus
B Ramapithecus
C Homo habilis
D Homo neanderthalensis.

The correct answer is:
Homo neanderthalensis.

Solution:
Homo habilis- 680 - 720 c.c
Homoerectus erectus- 775 - 990 c.c.,
Homo erectuspekinesis-915-1200 c.c.
Homonenderthalensis- 1300-1600 c.c.

Topic: Biology, Evolution, NEET, NEET 2007
Among the human ancestors, the brain size was more than 1000 cc in

Options:
A Homo erectus
B Ramapithecus
C Homo habilis
D Homo neanderthalensis

The correct answer is:
Homo neanderthalensis

Solution:
Homo habilis had a cranial capacity in the range of 680 - 720 cc, and that of Homo erectus was about 900 cc, and Homo nenderthalensis was about 1400 cc.

Topic: Biology, Evolution, NEET
Among the isomeric alkanes of molecular formula C5H12, identify the one that on photochemical chlorination yields a single monochloride.

Options:
A isopentane
B n-pentane
C neo-pentane
D No such alkane is present

The correct answer is:
neo-pentane

Solution:
Correct Option is : (C)
neo-pentane

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Among the isomeric alkanes of molecular formula C5H12, identify the one that on photochemical chlorination yields four isomeric monochlorides.

Options:
A n-pentane
B 2-methyl butane
C neo-pentane
D No such alkane is present

The correct answer is:
2-methyl butane

Solution:
Correct Option is : (B)
2-methyl butane

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Among the isomeric alkanes of molecular formula C5H12, identify the one that on photochemical chlorination yields three isomeric monochlorides.

Options:
A neo-pentane
B isopentane
C No such alkane is present
D n-pentane

The correct answer is:
n-pentane

Solution:
Correct Option is : (D)
n-pentane

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Among the isomeric dihalobenzenes, which isomer has the highest melting point?

Options:
A Ortho-isomers
B Meta-isomers
C Para-isomers
D None of them have a higher melting point.

The correct answer is:
Para-isomers

Solution:
Para-isomers have a higher melting point compared to their ortho- and meta-isomers.

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Among the listed ions, which one has a d10 electron configuration?

Options:
A Sc3+
B Zn2+
C Mn2+
D V2+

The correct answer is:
Zn2+

Solution:
Zn2+ has a stable d10 configuration.

Topic: Chemistry, d and f Block Elements, NEET
Among the listed ligands, which is expected to produce a weak field and result in a small crystal field splitting?

Options:
A F–
B NH3
C CO
D S2–

The correct answer is:
F–

Solution:
F– is expected to produce a weak field among the listed ligands, leading to a small crystal field splitting.

Topic: Chemistry, Coordination Compounds, NEET
Among the members of the list given below, how many plants have superior ovaries?
China rose, mustard, brinjal, potato, guava, cucumber, onion and tulip.

Options:
A Six
B Three
C Four
D Five

The correct answer is:
Six

Solution:
A superior ovary is found in plants of china rose, mustard, brinjal, potato, onion and tulip.

Topic: Biology, Morphology of Flowering Plants, NEET, NEET 2015 (Phase 2)
Among the members of the list given below, how many plants have superior ovary?

China rose, mustard, brinjal, potato, guava, cucumber, onion and tulip.

Options:
A Six
B Three
C Four
D Five

The correct answer is:
Six

Solution:
A superior ovary is found in plants of china rose, mustard, brinjal, potato, onion and tulip.

Topic: Biology, Morphology of Flowering Plants, NEET
Among the Newman and Sawhorse projections for the eclipsed and staggered conformations of ethane, which of these conformations is more stable and why?

Options:
A The eclipsed conformation in the Newman projection is more stable because it has lower steric hindrance.
B The eclipsed conformation in the Sawhorse projection is more stable because it has lower steric hindrance.
C The staggered conformation in the Sawhorse projection is more stable because it has higher steric hindrance.
D Among staggered and eclipsed conformation of ethane, staggered conformation is more stable than eclipsed conformation as in staggered form, the electron clouds of carbon-hydrogen bonds are as far apart as possible. Thus, there are minimum repulsive forces, minimum energy/ torsional strain and maximum stability of the molecule

The correct answer is:
Among staggered and eclipsed conformation of ethane, staggered conformation is more stable than eclipsed conformation as in staggered form, the electron clouds of carbon-hydrogen bonds are as far apart as possible. Thus, there are minimum repulsive forces, minimum energy/ torsional strain and maximum stability of the molecule

Solution:
Correct Option is : (D)
Among staggered and eclipsed conformation of ethane, staggered conformation is more stable than eclipsed conformation as in staggered form, the electron clouds of carbon-hydrogen bonds are as far apart as possible. Thus, there are minimum repulsive forces, minimum energy/ torsional strain and maximum stability of the molecule

Topic: Chemistry, Hydrocarbons, NEET
Among the oxides of Group 16 elements, which one is solid?

Options:
A Ozone (O3)
B Sulphur dioxide (SO2)
C Selenium dioxide (SeO2)
D Tellurium dioxide (TeO2)

The correct answer is:
Selenium dioxide (SeO2)

Solution:
The paragraph mentions that selenium dioxide (SeO2) is solid.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Among the oxyacids of phosphorous the dibasic acid is

Options:
A H3PO2
B H4P2O7
C HPO3
D H3PO3

The correct answer is:
H3PO3

Solution:
(A)
(B)
(C) exist as trimer
(D)

Topic: Chemistry, General Organic Chemistry, NEET
Among the properties [A] reducing [B] oxidizing [C] complexing agent, the set of properties shown by CN- ion towards metal species is

Options:
A A,B
B B,C
C C,A
D A,B,C

The correct answer is:
C,A

Solution:
The CN- ions acts as a ligand and reducing agent. In k3FeCN6 and k4FeCN6, CN- ions act a completing agent

Topic: Chemistry, Coordination Compounds, NEET
Among the second-period elements, the actual ionisation enthalpies are in the order Li < B < Be < C < O < N < F < Ne. Which of the following options explains why Be has a higher ionisation enthalpy than B?

Options:
A Beryllium has a smaller atomic size compared to boron.
B Beryllium has a higher effective nuclear charge (Zeff) than boron.
C The electronic configuration of Be has higher stability than the electronic configuration of B due to completely filled 2s orbital
D Beryllium has more protons in its nucleus compared to boron.

The correct answer is:
The electronic configuration of Be has higher stability than the electronic configuration of B due to completely filled 2s orbital

Solution:
Correct Option is : (C)
The electronic configuration of Be has higher stability than the electronic configuration of B due to completely filled 2s orbital

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Among the second-period elements, the actual ionisation enthalpies are in the order Li < B < Be < C < O < N < F < Ne Which of the following options explains why Oxygen has lower ∆iH than N and F?

Options:
A because Oxygen has more protons in its nucleus than N and F.
B because Oxygen has a larger atomic size compared to N and F.
C because Oxygen has a half-filled p-subshell, which makes it easier to remove an electron
D because Nitrogen has a half-filled stable electronic configuration and Fluorine has a higher Zeffas well as smaller size

The correct answer is:
because Nitrogen has a half-filled stable electronic configuration and Fluorine has a higher Zeffas well as smaller size

Solution:
Correct Option is : (D)
because Nitrogen has a half-filled stable electronic configuration and Fluorine has a higher Zeffas well as smaller size

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Among the seven pairs of contrasting traits in pea plant as studied by Mendel, the number of traits related to flower, pod, and seed respectively were ______.

Options:
A 2,2,2
B 2,2,1
C 1,2,2
D 1,1,2

The correct answer is:
2,2,2

Solution:
Johann Mendel considered the "Father of Genetics", gave the observation and theories of inheritance of characteristics. He made the bases of his conclusions on experiments conducted on Pisum sativum, pea plant. He had considered seven characteristics in the plant: seed shape, seed color, pod shape, pod color, stem height, flower color, flower position.

The number of flower, pod, and seed traits was two each and one for the stem of the plant.

Topic: Biology, Principles of Inheritance and Variation, NEET