datavorous/entrance-exam-dataset huggingface dataset:
Why are molecular orbitals obtained from 2px and 2py orbitals not symmetrical around the bond axis?

Options:
A Due to the presence of positive lobes above and positive lobes below the molecular plane.
B Due to the presence of negative lobes above and negative lobes below the molecular plane.
C Due to the presence of positive lobes above and negative lobes below the molecular plane.
D Due to the presence of negative lobes above and positive lobes below the molecular plane.

The correct answer is:
Due to the presence of positive lobes above and negative lobes below the molecular plane.

Solution:
Molecular orbitals obtained from 2px and 2py orbitals are not symmetrical around the bond axis because of the presence of positive lobes above and negative lobes below the molecular plane.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
Why are most hydrides formed by d-block and f-block elements almost always non-stoichiometric?

Options:
A They contain excess hydrogen atoms.
B They have a different lattice structure from their parent metals.
C They lack hydrogen atoms.
D They obey the law of constant composition.

The correct answer is:
They have a different lattice structure from their parent metals.

Solution:
Most hydrides formed by d-block and f-block elements are almost always non-stoichiometric because they have a different lattice structure from that of their parent metals, leading to variations in hydrogen content and not obeying the law of constant composition.

Topic: Chemistry, Hydrogen, NEET
Why are most hydrides of d-block and f-block elements considered non-stoichiometric?

Options:
A They have a surplus of hydrogen atoms.
B They lack hydrogen atoms.
C They have a different lattice structure from their parent metals.
D They follow the law of constant composition.

The correct answer is:
They have a different lattice structure from their parent metals.

Solution:
Most hydrides of d-block and f-block elements are non-stoichiometric because they possess a different lattice structure from their parent metals, resulting in varying hydrogen content.

Topic: Chemistry, Hydrogen, NEET
Why are most naturally occurring amino acids optically active?

Options:
A Because they have an asymmetric α-carbon atom
B Because they have a symmetric α-carbon atom
C Because they have a chiral side chain
D Because they have a non-chiral side chain

The correct answer is:
Because they have an asymmetric α-carbon atom

Solution:
The most naturally occurring amino acids are optically active because they have an asymmetric α-carbon atom, which means it has four different substituents, making it chiral.

Topic: Chemistry, Biomolecules, NEET
Why are mountain roads generally made winding upwards rather than going straight up?

Options:
A To increase the scenic beauty for tourists.
B To decrease the length of the road.
C To reduce the force of friction and minimize the chance of skidding.
D To make the journey more adventurous and thrilling.

The correct answer is:
To reduce the force of friction and minimize the chance of skidding.

Solution:
Correct Option is : (C)
To reduce the force of friction and minimize the chance of skidding.

Topic: Chemistry, Laws of Motion, NEET
Why are noble gases generally least reactive?

Options:
A They have completely filled valence shells
B They have high ionization enthalpy
C They have low electron gain enthalpy
D They have strong covalent bonds

The correct answer is:
They have completely filled valence shells

Solution:
Noble gases are generally the least reactive because they have completely filled ns²np⁶ electronic configurations in their valence shells.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Why are only p-orbital electrons involved in bonding for some elements in the group 13?

Options:
A Due to their high ionization enthalpies
B Due to the poor shielding effect of intervening d and f orbitals
C Due to their low melting points
D Due to their low electronegativity

The correct answer is:
Due to the poor shielding effect of intervening d and f orbitals

Solution:
Down the group, due to poor shielding effect of intervening d and f orbitals, the increased effective nuclear charge holds ns electrons tightly (responsible for inert pair effect) and thereby, restricting their participation in bonding. As a result of this, only p-orbital electron may be involved in bonding.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Why are organo-phosphates and carbamates considered harmful to humans?

Options:
A They are water-soluble
B They are highly persistent
C They are severe nerve toxins
D They are biodegradable

The correct answer is:
They are severe nerve toxins

Solution:
Organo-phosphates and carbamates are considered harmful to humans because they are severe nerve toxins.

Topic: Chemistry, Environmental Chemistry, NEET
Why are oxide ores preferred for extracting iron?

Options:
A They produce less pollution
B They yield higher metal content
C They are scarce and valuable
D They are easier to mine

The correct answer is:
They produce less pollution

Solution:
Oxide ores, chosen for iron extraction, don't produce polluting gases like SO2, unlike iron pyrites.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, NEET
Why are pentahalides of P, As, Sb, and Bi more covalent than their trihalides?

Options:
A Due to a decrease in atomic size.
B Due to an increase in atomic size.
C Due to an increase in the oxidation state.
D Due to the involvement of more valence electrons in bonding.

The correct answer is:
Due to the involvement of more valence electrons in bonding.

Solution:
Correct Option is : (D)
Due to the involvement of more valence electrons in bonding.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Why are perfectly elastic collisions important for the behavior of gases?

Options:
A They lead to an increase in kinetic energy
B They keep the total energy constant
C They cause gases to settle down
D They result in a loss of kinetic energy

The correct answer is:
They keep the total energy constant

Solution:
Perfectly elastic collisions are important for gases because they keep the total energy of gas molecules constant.

Topic: Chemistry, States of Matter, NEET
Why are porcelain objects wrapped in paper or straw before packing for transportation?

Options:
A To increase the overall weight of the package
B To make it easier to identify the contents
C To protect them from sudden impacts during transportation
D To improve the aesthetic appeal during unpacking

The correct answer is:
To protect them from sudden impacts during transportation

Solution:
Correct Option is : (C)
To protect them from sudden impacts during transportation

Topic: Chemistry, Laws of Motion, NEET
Why are potassium and caesium, rather than lithium used in photoelectric cells?

Options:
A Because potassium and caesium have higher ionization energies compared to lithium.
B Because potassium and caesium have lower ionization energies compared to lithium.
C Because potassium and caesium have higher electronegativities compared to lithium.
D Because potassium and caesium have lower electronegativities compared to lithium.

The correct answer is:
Because potassium and caesium have lower ionization energies compared to lithium.

Solution:
Correct Option is : (B)
Because potassium and caesium have lower ionization energies compared to lithium.

Topic: Chemistry, s Block Elements, NEET
Why are powdered substances more effective adsorbents than their crystalline forms?

Options:
A Because powdered substances have a larger surface area, providing more sites for adsorption.
B Because powdered substances have a lower surface energy, making them more attractive to adsorbates.
C Because powdered substances have stronger intermolecular forces, enhancing adsorption.
D Because powdered substances are more chemically reactive, leading to better adsorption.

The correct answer is:
Because powdered substances have a larger surface area, providing more sites for adsorption.

Solution:
Correct Option is : (A)
Because powdered substances have a larger surface area, providing more sites for adsorption.

Topic: Chemistry, Surface Chemistry, NEET
Why are reactions with molecularity three slow to proceed?

Options:
A Because they involve highly reactive species.
B Because they produce complex products.
C Because the probability of more than three molecules colliding simultaneously is very low.
D Because they require high temperatures to occur.

The correct answer is:
Because the probability of more than three molecules colliding simultaneously is very low.

Solution:
Reactions with molecularity three are slow to proceed because the probability of more than three molecules colliding simultaneously is very low.

Topic: Chemistry, Chemical Kinetics, NEET
Why are rubbers called elastomers?

Options:
A Because they are highly reactive
B Because they are excellent electrical conductors
C Rubbers are stretched on application of force and regain original state after the force is removed. Therefore these are called elastomers.
D Because they are highly resistant to heat

The correct answer is:
Rubbers are stretched on application of force and regain original state after the force is removed. Therefore these are called elastomers.

Solution:
Correct Option is : (C)
Rubbers are stretched on application of force and regain original state after the force is removed. Therefore these are called elastomers.

Topic: Chemistry, Polymers, NEET
Why are silicones water-repelling in nature?

Options:
A Because they contain water
B Because they contain polar groups
C Because they contain alkyl groups
D Because they contain silicon dioxide

The correct answer is:
Because they contain alkyl groups

Solution:
Silicones are water-repelling in nature because they are surrounded by non-polar alkyl groups.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Why are soaps and synthetic detergents used in cleansing?

Options:
A To increase water's ability to bind to fats
B To enhance the color of fabrics and skin
C To purify water for drinking
D To remove fats that bind other materials to fabrics or skin

The correct answer is:
To remove fats that bind other materials to fabrics or skin

Solution:
Soaps and synthetic detergents are used in cleansing to help remove fats that bind other materials to fabrics or skin.

Topic: Chemistry, Chemistry in Everyday Life, NEET
Why are solids incompressible?

Options:
A Because their particles are closely packed and resist compression.
B Because they lack intermolecular forces.
C Because they have a low density.
D Because they are always in a gaseous state.

The correct answer is:
Because their particles are closely packed and resist compression.

Solution:
Correct Option is : (A)
Because their particles are closely packed and resist compression.

Topic: Chemistry, Solid State, NEET
Why are solids rigid?

Options:
A Because their molecules oscillate.
B Because their molecules have fixed positions.
C Because they can flow easily.
D Because they are composed of carbon nanotubes.

The correct answer is:
Because their molecules have fixed positions.

Solution:
Solids are rigid because the constituent particles in solids have fixed positions and can only oscillate about their mean positions, as mentioned in the paragraph.

Topic: Chemistry, Solid State, NEET
Why are solids rigid?

Options:
A Due to the high kinetic energy of particles.
B Due to the strong forces of attraction between particles.
C Due to the constant motion of particles.
D Due to the low density of particles.

The correct answer is:
Due to the strong forces of attraction between particles.

Solution:
Correct Option is : (B)
Due to the strong forces of attraction between particles.

Topic: Chemistry, Solid State, NEET
Why are some medicines more effective in the colloidal form?

Options:
A Colloidal medicines have enhanced flavor.
B Colloidal medicines have higher chemical reactivity.
C Colloidal medicines have increased surface area for absorption.
D Colloidal medicines have a longer shelf life.

The correct answer is:
Colloidal medicines have increased surface area for absorption.

Solution:
Correct Option is : (C)
Colloidal medicines have increased surface area for absorption.

Topic: Chemistry, Surface Chemistry, NEET
Why are some polymers responsible for the accumulation of solid waste materials in the environment?

Options:
A Because they are resistant to degradation processes
B Because they are highly soluble in water
C Because they break down rapidly
D Because they are naturally occurring

The correct answer is:
Because they are resistant to degradation processes

Solution:
Some polymers are responsible for the accumulation of solid waste materials in the environment because they are resistant to degradation processes and do not break down easily.

Topic: Chemistry, Polymers, NEET
Why are statements of probability used in the quantum mechanical model of the atom?

Options:
A Because electrons have definite positions and momenta.
B Because it simplifies the calculations.
C Because the classical picture of electron motion is accurate.
D Because of the large uncertainties in position and velocity.

The correct answer is:
Because of the large uncertainties in position and velocity.

Solution:
The statements of probability are used in the quantum mechanical model of the atom because of the large uncertainties in position and velocity when trying to determine the exact location of electrons.

Topic: Chemistry, Structure of Atom, NEET
Why are sulfide ores converted to oxide before reduction?

Options:
A Oxides have a higher melting point, making them easier to handle during reduction.
B Sulfides are not reduced easily but oxides are easily reduced.
C Sulphides are not stable at high temperatures and can release toxic gases.
D Oxides are better conductors of electricity, facilitating the reduction process.

The correct answer is:
Sulfides are not reduced easily but oxides are easily reduced.

Solution:
Correct Option is : (B)
Sulfides are not reduced easily but oxides are easily reduced.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, NEET
Why are sulphide ores usually converted to oxides before reduction during metal extraction?

Options:
A Because sulphides are harder to handle
B Because oxides are easier to reduce
C Because oxides are harder to reduce
D Because sulphides are easier to handle

The correct answer is:
Because oxides are easier to reduce

Solution:
Sulphide ores are converted to oxides before reduction because oxides are easier to reduce during the extraction process.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, NEET
Why are synthetic detergents suitable for use in both soft and hard water?

Options:
A Because they are less effective in hard water
B Because they are made from natural sources
C Because they contain soap
D Because they give foam even in hard water

The correct answer is:
Because they give foam even in hard water

Solution:
Synthetic detergents can be used in both soft and hard water because they give foam even in hard water.

Topic: Chemistry, Chemistry in Everyday Life, NEET
Why are the atomic radii of noble gases not considered in the context of covalent or metallic radii?

Options:
A Because noble gases are not elements
B Because noble gases are radioactive
C Because noble gases do not form bonds with other elements
D Because noble gases have variable atomic sizes

The correct answer is:
Because noble gases do not form bonds with other elements

Solution:
The atomic radii of noble gases are not considered in the context of covalent or metallic radii because noble gases do not form bonds with other elements.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Why are the axial bonds longer as compared to equatorial bonds in the case of PCl5?

Options:
A The axial bonds are longer due to decreased electron-electron repulsions in the axial position.
B The axial bonds are longer because the axial position experiences more steric hindrance than the equatorial position.
C The axial bonds are longer because of the greater ionic character in those bonds.
D The axial bonds are longer due to the presence of lone pairs on the central phosphorus atom.

The correct answer is:
The axial bonds are longer because the axial position experiences more steric hindrance than the equatorial position.

Solution:
Correct Option is : (B)
The axial bonds are longer because the axial position experiences more steric hindrance than the equatorial position.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
Why are the elements of Group 18 known as noble gases?

Options:
A They have high electronegativity values.
B They are unreactive due to their stable electronic configurations.
C They were historically associated with nobility.
D They are found in noble metals.

The correct answer is:
They are unreactive due to their stable electronic configurations.

Solution:
Correct Option is : (B)
They are unreactive due to their stable electronic configurations.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Why are the energy levels of He4 and He3, as calculated using the Bohr model, very close to each other upon removing one electron from each?

Options:
A Due to the similar atomic structure of both helium isotopes
B Because of the identical electronic configuration of He4 and He3
C Resulting from the nuclear charge overshadowing the electron's contribution
D Attributed to the quantum mechanical similarities between He4 and He3

The correct answer is:
Resulting from the nuclear charge overshadowing the electron's contribution

Solution:
Correct Option is : (C)
Resulting from the nuclear charge overshadowing the electron's contribution

Topic: Chemistry, Atomic Physics, NEET
Why are the EV values for Mn, Ni, and Zn more negative than expected?

Options:
A These elements have lower ionization energies.
B These elements have a greater affinity for electrons.
C These elements have more stable electronic configurations.
D These elements have higher ionization energies.

The correct answer is:
These elements have more stable electronic configurations.

Solution:
Correct Option is : (C)
These elements have more stable electronic configurations.

Topic: Chemistry, d and f Block Elements, NEET
Why are the first four members of alkanes (C1 to C4) in the gaseous state at 298 K?

Options:
A High electronegativity of carbon atoms
B Low molecular mass
C Presence of hydrogen bonding
D Strong van der Waals forces

The correct answer is:
Low molecular mass

Solution:
The first four members of alkanes (C1 to C4) are in the gaseous state at 298 K because of their low molecular mass and weak intermolecular forces.

Topic: Chemistry, Hydrocarbons, NEET
Why are the fluorides of alkaline earth metals relatively less soluble than the chlorides?

Options:
A Due to their lower lattice energies
B Due to their higher lattice energies
C Due to their covalent nature
D Due to their ionic nature

The correct answer is:
Due to their higher lattice energies

Solution:
The fluorides of alkaline earth metals are relatively less soluble than the chlorides because they have higher lattice energies.

Topic: Chemistry, s Block Elements, NEET
Why are the monomeric trihalides strong Lewis acids?

Options:
A Because they have a full electron octet
B Because they are electron-rich
C Because they are electron-deficient
D Because they contain d orbitals

The correct answer is:
Because they are electron-deficient

Solution:
The monomeric trihalides are electron deficient, which makes them strong Lewis acids.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Why are the oxides of iodine more stable compared to chlorine and bromine oxides?

Options:
A Due to the availability of d-orbitals in iodine
B Due to greater polarisability of the bond between iodine and oxygen
C Due to multiple bond formation between chlorine and oxygen
D Due to the middle row anomaly

The correct answer is:
Due to greater polarisability of the bond between iodine and oxygen

Solution:
The higher stability of the oxides of iodine is due to the greater polarisability of the bond between iodine and oxygen.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Why are the properties of amorphous solids the same in all directions?

Options:
A Because of their high density
B Because they are transparent
C Because there is no definite arrangement of particles along any direction
D Because they have a crystalline structure

The correct answer is:
Because there is no definite arrangement of particles along any direction

Solution:
The properties of amorphous solids are the same in all directions because there is no definite arrangement of particles along any direction, as stated in the paragraph.

Topic: Chemistry, Solid State, NEET
Why are the trihalides of nitrogen exceptional?

Options:
A Nitrogen has unique electron configuration
B Nitrogen has a small atomic size
C Nitrogen is highly electronegative
D Nitrogen can form strong hydrogen bonds

The correct answer is:
Nitrogen has unique electron configuration

Solution:
The exceptional behavior of nitrogen's trihalides is due to its unique electron configuration.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Why are the trihalides of nitrogen unstable?

Options:
A Nitrogen has a high ionization energy
B Nitrogen is a non-metal
C Nitrogen's small atomic size
D All the trihalides of nitrogen are not unstable

The correct answer is:
All the trihalides of nitrogen are not unstable

Solution:
The paragraph mentions that all the trihalides of these elements, except those of nitrogen, are stable.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Why are the values of colligative properties in colloidal solutions compared to true solutions?

Options:
A To determine the size of particles
B To determine the type of particles
C To compare their order of magnitude
D To measure the concentration

The correct answer is:
To compare their order of magnitude

Solution:
The values of colligative properties in colloidal solutions are compared to true solutions to compare their order of magnitude.

Topic: Chemistry, Surface Chemistry, NEET
Why are these voids called tetrahedral voids?

Options:
A Because they are square in shape
B Because they are hexagonal in shape
C Because a tetrahedron is formed when the centres of four spheres surrounding the void are joined
D Because they are octahedral in shape

The correct answer is:
Because a tetrahedron is formed when the centres of four spheres surrounding the void are joined

Solution:
These voids are called tetrahedral voids because a tetrahedron is formed when the centres of the four spheres surrounding the void are joined, as mentioned in the paragraph.

Topic: Chemistry, Solid State, NEET
Why are transgenic mice being developed?

Options:
A To study the regulation of genes
B To test the safety of vaccines
C To increase the size of mice
D To enhance their physical abilities

The correct answer is:
To test the safety of vaccines

Solution:
Transgenic mice are being developed for use in testing the safety of vaccines before they are used on humans.

Topic: Biology, Biotechnology and Its Applications, NEET
Why are transition elements different from non-transition elements?

Options:
A They have different atomic numbers.
B They have different chemical reactivity.
C They have partly filled d or f orbitals.
D They have different valence electrons.

The correct answer is:
They have partly filled d or f orbitals.

Solution:
Transition elements are different from non-transition elements because of the presence of partly filled d or f orbitals in their atoms.

Topic: Chemistry, d and f Block Elements, NEET
Why are zeolites considered good shape-selective catalysts?

Options:
A Due to their color
B Due to their size
C Due to their honeycomb-like structures
D Due to their natural occurrence

The correct answer is:
Due to their honeycomb-like structures

Solution:
The paragraph states that zeolites are good shape-selective catalysts because of their honeycomb-like structures.

Topic: Chemistry, Surface Chemistry, NEET