datavorous/entrance-exam-dataset huggingface dataset:
Why are Zn, Cd, and Hg exceptions among the transition elements?

Options:
A They are radioactive.
B They are non-metals.
C They have a filled d subshell.
D They are found in the inner core of the Earth.

The correct answer is:
They have a filled d subshell.

Solution:
Zn, Cd, and Hg are exceptions among the transition elements because they have a filled d subshell.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Why are Zn, Cd, Hg, and Cn not regarded as transition elements?

Options:
A They have incomplete d orbitals
B They have completely filled d orbitals
C They have a variety of oxidation states
D They exhibit paramagnetic behaviour

The correct answer is:
They have completely filled d orbitals

Solution:
Zn, Cd, Hg, and Cn are not regarded as transition elements because their d orbitals are completely filled in the ground state as well as in their common oxidation states.

Topic: Chemistry, d and f Block Elements, NEET
Why BF3 is non-polar and NF3 is polar although BF3 and NF3 both molecules are covalent?

Options:
A In uncombined state boron is metal and nitrogen is gas
B B-F bond has no dipole moment whereas N-F bond has dipole moment
C The size of boron atom is smaller than nitrogen
D BF3 is planar whereas NF3 is pyramidal

The correct answer is:
BF3 is planar whereas NF3 is pyramidal

Solution:
BF3 is planar while NF3 is pyramidal due to the presence of lone pair of electron on nitrogen in NF3.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
Why both strands of DNA are not copied during transcription?

Options:
A Complementary sequences would code for two different proteins
B The two RNA molecules produced would be complementary to each other
C The DNA strands are identical
D Both A) and B)

The correct answer is:
Both A) and B)

Solution:
If both strands of DNA act as templates, they would code for RNA molecules with different sequences. Additionally, the two RNA molecules produced would be complementary to each other, which would prevent RNA from being translated into protein.

Topic: Biology, Molecular Basis of Inheritance, NEET
Why can aryl halides not be prepared by reaction of phenol with HCl in the presence of ZnCl2?

Options:
A C—O bond in phenols is more stable due to resonance effect and it has double bond character, hence breaking of this bond is difficult.
B ZnCl2acts as a reducing agent, preventing halogenation.
C Phenol and HCl do not form a suitable reaction mixture.
D ZnCl2reacts with HCl to form an unreactive complex.

The correct answer is:
C—O bond in phenols is more stable due to resonance effect and it has double bond character, hence breaking of this bond is difficult.

Solution:
Correct Option is : (A)
C—O bond in phenols is more stable due to resonance effect and it has double bond character, hence breaking of this bond is difficult.

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Why can dilute solutions of hydrogen peroxide not be concentrated by heating. How can a concentrated solution of hydrogen peroxide be obtained?

Options:
A Dilute solutions decompose upon heating.
B Dilute solutions are non-volatile.
C Dilute solutions evaporate and escape as gas.
D Dilute solutions react with metals.

The correct answer is:
Dilute solutions decompose upon heating.

Solution:
Correct Option is : (A)
Dilute solutions decompose upon heating.

Topic: Chemistry, Hydrogen, NEET
Why can elements like aluminum have a maximum covalence beyond 4?

Options:
A They have a greater atomic number
B They have available d orbitals
C They have fewer valence electrons
D They have a larger atomic radius

The correct answer is:
They have available d orbitals

Solution:
Elements like aluminum can have a maximum covalence beyond 4 because they have available d orbitals.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Why can excessive hydrogencarbonate be problematic in treating acidity?

Options:
A It decreases pH in the stomach.
B It triggers the production of more acid.
C It makes the stomach alkaline.
D It does not affect acidity.

The correct answer is:
It makes the stomach alkaline.

Solution:
Excessive hydrogencarbonate can make the stomach alkaline, which can be problematic in treating acidity.

Topic: Chemistry, Chemistry in Everyday Life, NEET
Why can high concentrations of ozone be dangerously explosive?

Options:
A Because ozone can easily liberate nascent oxygen
B Because ozone is highly flammable
C Because ozone rapidly decomposes into nitrogen
D Because ozone is corrosive

The correct answer is:
Because ozone can easily liberate nascent oxygen

Solution:
High concentrations of ozone can be dangerously explosive because ozone readily liberates nascent oxygen (O3

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Why can molecularity not be zero or a non-integer?

Options:
A Because it is a theoretical concept
B Because it is determined experimentally
C Because it is always equal to the order of the reaction
D Because it represents the number of reacting species colliding simultaneously

The correct answer is:
Because it represents the number of reacting species colliding simultaneously

Solution:
Molecularity represents the number of reacting species colliding simultaneously in an elementary reaction, and it cannot be zero or a non-integer.

Topic: Chemistry, Chemical Kinetics, NEET
Why can most tetrachlorides be easily hydrolyzed by water?

Options:
A They contain a high concentration of chlorine atoms.
B They readily react with water molecules.
C The central atom can accommodate the lone pair of electrons from oxygen atom of water molecule in d orbital.
D They are highly soluble in water.

The correct answer is:
The central atom can accommodate the lone pair of electrons from oxygen atom of water molecule in d orbital.

Solution:
Most tetrachlorides can be easily hydrolyzed because the central atom can accommodate the lone pair of electrons from the oxygen atom of the water molecule in d orbital.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Why can nitrogen exhibit oxidation states from +1 to +4 but not +5 with halogens?

Options:
A Lack of electrons
B Presence of d-orbitals
C Inert pair effect
D Lack of oxygen

The correct answer is:
Presence of d-orbitals

Solution:
The paragraph states that nitrogen cannot form compounds in the +5 oxidation state with halogens because it lacks d-orbitals to accommodate electrons from other elements to form bonds.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Why can ozone and nitric acid act only as oxidants in their reactions?

Options:
A They have a high electronegativity.
B They have a low electron affinity.
C They have a high electron density.
D They contain a large number of oxygen atoms.

The correct answer is:
They have a high electronegativity.

Solution:
Correct Option is : (A)
They have a high electronegativity.

Topic: Chemistry, Redox Reactions, NEET
Why can pure liquids and solids be ignored while writing the equilibrium constant expression?

Options:
A They don't contribute to the equilibrium constant.
B They have a constant concentration.
C They have a negligible effect on the equilibrium.
D They are considered in the equilibrium constant.

The correct answer is:
They have a negligible effect on the equilibrium.

Solution:
Correct Option is : (C)
They have a negligible effect on the equilibrium.

Topic: Chemistry, Ionic Equilibrium, NEET
Why can sulfur dioxide and hydrogen peroxide act as both oxidizing and reducing agents in their reactions?

Options:
A They contain a high concentration of oxygen atoms.
B They can easily accept or donate electrons.
C They have a balanced number of protons and electrons.
D They are highly reactive with other elements.

The correct answer is:
They can easily accept or donate electrons.

Solution:
Correct Option is : (B)
They can easily accept or donate electrons.

Topic: Chemistry, Redox Reactions, NEET
Why can we not determine the order of a reaction by taking into consideration the balanced chemical equation?

Options:
A The order of a reaction cannot be determined using any method, as it is a constant value.
B Because order is determined experimentally and is confined to the dependence of observed rate of reaction on the concentration of reactants which is generally not equal to the sum of stoichiometric coefficients of the reactants
C The order of a reaction can be determined solely from the balanced chemical equation.
D The balanced chemical equation provides information about the activation energy of the reaction, not the order.

The correct answer is:
Because order is determined experimentally and is confined to the dependence of observed rate of reaction on the concentration of reactants which is generally not equal to the sum of stoichiometric coefficients of the reactants

Solution:
Correct Option is : (B)
Because order is determined experimentally and is confined to the dependence of observed rate of reaction on the concentration of reactants which is generally not equal to the sum of stoichiometric coefficients of the reactants

Topic: Chemistry, Chemical Kinetics, NEET
Why cannot aromatic primary amines be prepared by Gabriel phthalimide synthesis?

Options:
A Aromatic compounds do not react with phthalimide.
B Aromatic primary amines cannot be prepared by Gabriel phthalimide synthesis as aryl halides do not undergo nucleophilic substitution with the salt formed by phthalimide.
C Aromatic compounds are too stable to undergo nucleophilic substitution.
D Gabriel phthalimide synthesis is not suitable for any type of amine synthesis.

The correct answer is:
Aromatic primary amines cannot be prepared by Gabriel phthalimide synthesis as aryl halides do not undergo nucleophilic substitution with the salt formed by phthalimide.

Solution:
Correct Option is : (B)
Aromatic primary amines cannot be prepared by Gabriel phthalimide synthesis as aryl halides do not undergo nucleophilic substitution with the salt formed by phthalimide.

Topic: Chemistry, Amines, NEET
Why cannot vitamin C be stored in our body?

Options:
A The body stores vitamin C in limited quantities but cannot store it in large amounts.
B Our body lacks the necessary enzymes to absorb vitamin C.
C Vitamin C reacts with other nutrients in the body, rendering it non-storable.
D Vitamin C is water-soluble vitamin and excreted from the body through urine.

The correct answer is:
Vitamin C is water-soluble vitamin and excreted from the body through urine.

Solution:
Correct Option is : (D)
Vitamin C is water-soluble vitamin and excreted from the body through urine.

Topic: Chemistry, Biomolecules, NEET
Why can't aromatic primary amines be prepared by Gabriel synthesis?

Options:
A Aromatic compounds are unreactive.
B Aromatic compounds are too reactive.
C Aryl halides do not undergo nucleophilic substitution with the phthalimide anion.
D Aryl halides form stable complexes with phthalimide.

The correct answer is:
Aryl halides do not undergo nucleophilic substitution with the phthalimide anion.

Solution:
Aromatic primary amines cannot be prepared by Gabriel synthesis because aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.

Topic: Chemistry, Amines, NEET
Why can't the 2px or 2py orbitals combine with the 2pz orbital of another atom?

Options:
A They have different shapes.
B They have different electron configurations.
C They have the same symmetry.
D They have the same energy.

The correct answer is:
They have different shapes.

Solution:
The 2px or 2py orbitals cannot combine with the 2pz orbital of another atom because they have different symmetries.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
Why can't the molecularity of any reaction be equal to zero?

Options:
A Molecularity is the number of molecules taking part in an elementary step. For this we require at least a single molecule leading to the value of minimum molecularity of one.
B Molecularity can be zero, but it is rare in chemical reactions.
C Reactions with zero molecularity are very practical
D Molecularity is always equal to zero

The correct answer is:
Molecularity is the number of molecules taking part in an elementary step. For this we require at least a single molecule leading to the value of minimum molecularity of one.

Solution:
Correct Option is : (A)
Molecularity is the number of molecules taking part in an elementary step. For this we require at least a single molecule leading to the value of minimum molecularity of one.

Topic: Chemistry, Chemical Kinetics, NEET
Why can't the Solvay Process be used to manufacture potassium carbonate?

Options:
A Potassium hydrogen carbonate is too insoluble.
B Potassium hydrogen carbonate is too soluble.
C Potassium chloride is not available.
D Potassium hydroxide is too expensive.

The correct answer is:
Potassium hydrogen carbonate is too soluble.

Solution:
The Solvay Process cannot be extended to the manufacture of potassium carbonate because potassium hydrogencarbonate is too soluble to be precipitated by the addition of ammonium hydrogen carbonate to a saturated solution of potassium chloride.

Topic: Chemistry, s Block Elements, NEET
Why CH3+is the least stable cation?

Options:
A CH3+is the least stable cation because it has the highest electron density, leading to strong electron-electron repulsions.
B In CH3+, vacant p orbital is perpendicular to the plane in which C-H bonds lie; hence cannot overlap with it. Thus, CH3+lacks hyperconjugative stability.
C CH3+is the least stable cation because it is a highly polar molecule with a positive charge on carbon, making it prone to nucleophilic attack.
D CH3+is the least stable cation because it has an incomplete valence shell.

The correct answer is:
In CH3+, vacant p orbital is perpendicular to the plane in which C-H bonds lie; hence cannot overlap with it. Thus, CH3+lacks hyperconjugative stability.

Solution:
Correct Option is : (B)
In CH3+, vacant p orbital is perpendicular to the plane in which C-H bonds lie; hence cannot overlap with it. Thus, CH3+lacks hyperconjugative stability.

Topic: Chemistry, General Organic Chemistry, NEET
Why CNG is considered better fuel than diesel?
(a) It can not be adulterated
(b) It takes less time to fill the fuel tank
(c) It burns more efficiently
(d) It is cheaper
(e) It is less inflammable.
Choose the most appropriate answer from the options given below

Options:
A (a), (b), (c), (e) only
B (a), (c), (d) only
C (a), (b), (d), (e) only
D (c), (d), (e) only

The correct answer is:
(a), (c), (d) only

Solution:
CNG (Compressed Natural Gas) is better fuel than diesel because it cannot be adulterated, If burns more efficiently and It is cheaper than diesel.
$\rightarrow$ Its distribution is difficult.

Topic: Biology, Environmental Issues, NEET, NEET 2022 (Phase 2)
Why could the chemistry of tennessine not be established easily?

Options:
A It has a long half-life
B It is highly stable
C It is not a radioactive element
D It has a very short half-life

The correct answer is:
It has a very short half-life

Solution:
The chemistry of tennessine could not be established easily because it has a very short half-life measured in milliseconds, making it challenging to work with.**

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Why Cu+ion is not stable in aqueous solutions?

Options:
A Cu+has a higher ionization energy than Cu2+
B Cu+has a more stable electron configuration than Cu2+
C because Cu+ion in aqueous solution undergoes disproportionation
D Cu+is a stronger reducing agent than Cu2+

The correct answer is:
because Cu+ion in aqueous solution undergoes disproportionation

Solution:
Correct Option is : (C)
because Cu+ion in aqueous solution undergoes disproportionation

Topic: Chemistry, d and f Block Elements, NEET
Why did Mendeleev propose leaving gaps in his periodic table?

Options:
A Because he believed the order of atomic weights was incorrect.
B Because he wanted to make the table look more organized.
C Because he didn't know about those elements.
D Because he wanted to confuse other scientists.

The correct answer is:
Because he believed the order of atomic weights was incorrect.

Solution:
Mendeleev proposed leaving gaps in his periodic table because he believed the order of atomic weights might be incorrect.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Why did Morgan attribute a higher proportion of parental gene combinations to linkage?

Options:
A Due to the physical association or linkage of two genes on different chromosomes
B Due to the recombination of genes on different chromosomes
C Due to the physical association or linkage of two genes on the same chromosome
D Due to the recombination of genes on the same chromosome

The correct answer is:
Due to the physical association or linkage of two genes on the same chromosome

Solution:
Morgan observed that the proportion of parental gene combinations were much higher than the non:parental type when the two genes in a dihybrid cross were situated on the same chromosome, and attributed this to linkage.

Topic: Biology, Principles of Inheritance and Variation, NEET
Why did pouched mammals of Australia survive?

Options:
A Because of lack of competition from any other mammal
B Because of their intelligence
C Because of their viviparous nature
D Because of their physical strength

The correct answer is:
Because of lack of competition from any other mammal

Solution:
Due to continental drift, pouched mammals of Australia survived because of lack of competition from any other mammal.

Topic: Biology, Evolution, NEET
Why did RNA evolve into DNA?

Options:
A RNA being unstable
B RNA being a catalyst
C RNA having a shorter life span
D All of the above

The correct answer is:
RNA being unstable

Solution:
RNA evolved into DNA due to its instability and reactiveness as a catalyst. DNA has chemical modifications that make it more stable.

Topic: Biology, Molecular Basis of Inheritance, NEET
Why did the molecular formula of benzene, C6H6, indicate a high degree of unsaturation?

Options:
A Because it has a double bond
B Because it has a triple bond
C Because it contains only carbon and hydrogen atoms
D Because it reacts readily with other unsaturated compounds

The correct answer is:
Because it contains only carbon and hydrogen atoms

Solution:
The molecular formula C6H6 indicates a high degree of unsaturation because it contains only carbon and hydrogen atoms, suggesting the presence of multiple double or triple bonds.

Topic: Chemistry, Hydrocarbons, NEET
Why did the separation of components of a binary mixture of two liquids A and B by distillation stop, and both components started coming in the distillate with the composition of the liquid and vapor phases being the same?

Options:
A The distillation apparatus was not functioning properly.
B The temperature of the distillation process was too low.
C The liquids formed an azeotropic mixture, preventing further separation by distillation.
D The liquids were contaminated with impurities.

The correct answer is:
The liquids formed an azeotropic mixture, preventing further separation by distillation.

Solution:
Correct Option is : (C)
The liquids formed an azeotropic mixture, preventing further separation by distillation.

Topic: Chemistry, Solutions, NEET
Why did the white:winged moths not survive during the postindustrialization period?

Options:
A They were not able to camouflage themselves against the darker background caused by industrial smoke and soots
B They were not able to compete with the dark-winged moths for food
C They were not resistant to the pollutants in the environment
D They were not able to reproduce as effectively as the dark-winged moths

The correct answer is:
They were not able to camouflage themselves against the darker background caused by industrial smoke and soots

Solution:
Before industrialization set in, thick growth of almost white:colored lichen covered the trees, in that background the white winged moth survived but the dark-colored moth were picked out by predators. During postindustrialization period, the tree trunks became dark due to industrial smoke and soots. Under this condition the white:winged moth did not survive due to predators, dark-winged or melanized moth survived.

Topic: Biology, Evolution, NEET
Why do 3° alkyl halides undergo SN1 reactions very fast?

Options:
A Due to the high concentration of hydroxide ion
B Due to the high concentration of alkyl halide
C Due to the high stability of 3° carbocations
D Due to the high concentration of protic solvent

The correct answer is:
Due to the high stability of 3° carbocations

Solution:
3° alkyl halides undergo SN1 reactions very fast because of the high stability of 3° carbocations.

Topic: Chemistry, Haloalkanes and Haloarenes, NEET
Why do alcohols have higher boiling points compared to haloalkanes of similar molecular masses?

Options:
A Haloalkanes have stronger hydrogen bonds
B Alcohols have higher electronegativity
C Alcohols form ionic bonds
D Alcohols have hydrogen bonding

The correct answer is:
Alcohols have hydrogen bonding

Solution:
Alcohols have higher boiling points than haloalkanes due to the presence of hydrogen bonding.

Topic: Chemistry, Alcohols Phenols and Ethers, NEET
Why do aldehydes and ketones generally have higher boiling points than hydrocarbons and ethers of comparable molecular masses?

Options:
A Due to stronger covalent bonds
B Due to hydrogen bonding
C Due to dipole-dipole interactions
D Due to metallic bonding

The correct answer is:
Due to dipole-dipole interactions

Solution:
Aldehydes and ketones have higher boiling points than hydrocarbons and ethers of comparable molecular masses because of the presence of dipole-dipole interactions between their molecules.

Topic: Chemistry, Aldehydes, Ketones and Carboxylic Acids, NEET
Why do aldehydes and ketones generally have lower boiling points than alcohols of similar molecular masses?

Options:
A Due to stronger covalent bonds
B Due to hydrogen bonding
C Due to dipole-dipole interactions
D Due to metallic bonding

The correct answer is:
Due to hydrogen bonding

Solution:
Aldehydes and ketones have lower boiling points than alcohols of similar molecular masses because they lack the ability to form intermolecular hydrogen bonds. Alcohols can form hydrogen bonds, which require more energy to break, resulting in higher boiling points.

Topic: Chemistry, Aldehydes, Ketones and Carboxylic Acids, NEET
Why do alkali metals and halogens exhibit an increase in atomic size as you descend the groups?

Options:
A Because they have fewer valence electrons
B Because they have a higher effective nuclear charge
C Because the inner energy levels are filled with electrons
D Because they have a lower atomic number

The correct answer is:
Because the inner energy levels are filled with electrons

Solution:
As you descend the groups for alkali metals and halogens, the increase in atomic size is due to the inner energy levels being filled with electrons, which shield the outer electrons from the nucleus.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Why do amines behave as bases?

Options:
A Due to the presence of unshared electron pairs on nitrogen atoms.
B Due to their color.
C Due to their high molar mass.
D Due to the presence of oxygen atoms.

The correct answer is:
Due to the presence of unshared electron pairs on nitrogen atoms.

Solution:
Amines have unshared electron pairs on nitrogen atoms, making them capable of accepting protons and behaving as Lewis bases.

Topic: Chemistry, Amines, NEET
Why do amino acids behave like salts rather than simple amines or carboxylic acids?

Options:
A Because they are highly soluble in water
B Because they are high melting solids
C Because they contain both acidic and basic groups
D Because they are optically active

The correct answer is:
Because they contain both acidic and basic groups

Solution:
Amino acids behave like salts because they contain both acidic (carboxyl group) and basic (amino group) groups in the same molecule.

Topic: Chemistry, Biomolecules, NEET