datavorous/entrance-exam-dataset huggingface dataset:
Why is the Eo value for the Mn3+/Mn2+ redox couple much more positive than that for Cr3+/Cr2+ or Fe3+/Fe2+?

Options:
A Because Mn has more d electrons
B Because Mn has a larger atomic size
C Because Mn has a much larger third ionization energy
D Because Mn has a higher melting point

The correct answer is:
Because Mn has a much larger third ionization energy

Solution:
The much larger third ionization energy of Mn is mainly responsible for the more positive Eo value for the Mn3+/Mn2+ redox couple.

Topic: Chemistry, d and f Block Elements, NEET
Why is the hydrolysis of cane sugar described as a pseudo first order reaction?

Options:
A Because it involves only one reactant.
B Because it follows the rate law for first-order reactions.
C Because it produces only one product.
D Because it involves multiple reactants, but the concentration of one reactant remains constant.

The correct answer is:
Because it involves multiple reactants, but the concentration of one reactant remains constant.

Solution:
The inversion of cane sugar is another example of a pseudo first order reaction because it involves multiple reactants, but the concentration of one reactant (water in this case) remains constant.

Topic: Chemistry, Chemical Kinetics, NEET
Why is the NH2 group of aniline acetylated before carrying out nitration?

Options:
A Acetylation increases the reactivity of aniline toward nitration.
B The NH2group of aniline is acetylated before nitration to control the nitration reaction and the formation of tarry oxidation products and nitro derivatives. P-nitroaniline is the main product here.
C Acetylation enhances the solubility of aniline in the reaction mixture.
D Acetylation reduces the toxicity of aniline, making it safer to handle.

The correct answer is:
The NH2group of aniline is acetylated before nitration to control the nitration reaction and the formation of tarry oxidation products and nitro derivatives. P-nitroaniline is the main product here.

Solution:
Correct Option is : (B)
The NH2group of aniline is acetylated before nitration to control the nitration reaction and the formation of tarry oxidation products and nitro derivatives. P-nitroaniline is the main product here.

Topic: Chemistry, Amines, NEET
Why is the oxidation of a primary alcohol witha mixture of sodium dichromate and sulphuric acid not a good method for the preparation of corresponding aldehyde?

Options:
A The product will be the corresponding ketone
B Any aldehyde produced will be oxidised further
C The product will be an alkyl sulphonate, R-SO3H mixture of sodium dichromate and sulphuric acid will not oxidize a primary alcohol
D A mixture of sodium dichromate and sulphuric acid will not oxidised a primary alcohol

The correct answer is:
Any aldehyde produced will be oxidised further

Solution:
Primary alcohols can be oxidized to either aldehydes or carboxylic acids depending on the reaction conditions. In the case of the formation of carboxylic acids, the alcohol is first oxidized to an aldehyde which is then oxidized further to the acid.
Primary Alcohol →O Aldehyde →OCarboxylicacid
So, any aldehyde produced will be oxidized further during the reaction.

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Why is the work done by the gravitational force on a comet, which moves around the sun in highly elliptical orbits where the gravitational force is not normal to the comet's velocity, zero over every complete orbit?

Options:
A The gravitational force on the comet is always perpendicular to its velocity.
B The comet's velocity remains constant throughout its orbit.
C The work done by the gravitational force is canceled out by the kinetic energy of the comet.
D The work done by the gravitational force is compensated by the potential energy changes in the comet-sun system.

The correct answer is:
The work done by the gravitational force is compensated by the potential energy changes in the comet-sun system.

Solution:
Correct Option is : (D)
The work done by the gravitational force is compensated by the potential energy changes in the comet-sun system.

Topic: Chemistry, Work Power Energy, NEET
Why is there a pressure to switch to organic farming?

Options:
A To decrease environmental pollution
B To increase demand for agricultural produce
C To switch to conventional farming
D To improve the soil nutrient quality

The correct answer is:
To decrease environmental pollution

Solution:
There is a large pressure to switch to organic farming, mainly because of the problems associated with the overuse of chemical fertilisers and to decrease environmental pollution.

Topic: Biology, Microbes in Human Welfare, NEET
Why on dilution the Λmof CH3COOH increases drastically, while that of CH3COONa increases gradually?

Options:
A CH3COOH has more ions than CH3COONa.
B In the case of CH3COOH, which is a weak electrolyte, the number of ions increase on dilution due to an increase in degree of dissociation.In the case of strong electrolyte the number of ions remains the same but the interionic attraction decreases
C CH3COOH undergoes complete ionization upon dilution.
D CH3COONa has a higher initial molar conductivity than CH3COOH.

The correct answer is:
In the case of CH3COOH, which is a weak electrolyte, the number of ions increase on dilution due to an increase in degree of dissociation.In the case of strong electrolyte the number of ions remains the same but the interionic attraction decreases

Solution:
Correct Option is : (B)
In the case of CH3COOH, which is a weak electrolyte, the number of ions increase on dilution due to an increase in degree of dissociation.In the case of strong electrolyte the number of ions remains the same but the interionic attraction decreases

Topic: Chemistry, Electrochemistry, NEET
Why plasma proteins are important?

Options:
A They are involved in the defence mechanism of the body
B They aid in maintaining the osmotic balance of the body
C It plays a significant role in blood coagulation
D All of the above

The correct answer is:
All of the above

Solution:
They are involved in the defence mechanism of the body, They aid in maintaining the osmotic balance of the body, It plays a significant role in blood coagulation are importance of plasma proteins

Topic: Biology, Body Fluids and Circulation, NEET
Width of the principal maximum on a screen at a distance of 50 cm from the slit having width 0.02 cm is 312.5Ã10-3 cm . If waves were incident normally on the slit, then wavelength of the light from the source will be

Options:
A 6000Â â«
B 6250 â«
C 6400Â â«
D 6525Â â«

The correct answer is:
6250 â«

Solution:
Width of central max. =2 Î»Da
Î»=0.2Ã10-2Ã312.5Ã10-3Ã10-22Ã12m
=6250Ã10-10 m=6250 â«

Topic: Physics, Wave Optics, JEE Main
Wilkinson catalyst is

Options:
A Et3P3IrCl Et=C2H5
B Ph3P3RhCl
C Ph3P3IrCl
D Et3P3RhCl

The correct answer is:
Ph3P3RhCl

Solution:
Chlorotris(triphenylphosphine)rhodium(I) is known as Wilkinson's catalyst. It is used as a homogeneous hydrogenation catalyst. It is a square planar 16-electron complex. The oxidation state of Rhodium in it is +1.

Topic: Chemistry, Coordination Compounds, JEE Main, JEE Main 2019 (10 Jan Shift 1)
Williamson synthesis of ether is an example of :

Options:
A Nucleophilic substitution
B Electrophilic addition
C Nucleophilic addition
D Electrophilic substitution

The correct answer is:
Nucleophilic substitution

Solution:
The Williamson ether synthesis is the most widely used method to synthesize ethers. It occurs by an SN2 reaction in which a metal alkoxide displaces a halide ion from an alkyl halide.
RO-+R'-x→SNR-O-R'
This is Nucleophilic substitution reaction.

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main, JEE Main 2014 (19 Apr Online)
Williamson's synthesis involves

Options:
A $\mathrm{S}_{\mathrm{N}} 1$ mechanism
B nucleophilic addition
C $\mathrm{S}_{\mathrm{N}} 2$ mechanism
D $\mathrm{S}_{\mathrm{E}}$ mechanism

The correct answer is:
$\mathrm{S}_{\mathrm{N}} 2$ mechanism

Solution:
When sodium or potassium alkoxide is heated with an alkyl halide to give ether, this reaction is known as Williamson's synthesis.
$$
R \mathrm{ONa}+R^{\prime} X \longrightarrow R-\mathrm{O}-R^{\prime}+\mathrm{Na} X
$$
This is an example of nucleophilic substitution and follow $\mathrm{S}_{\mathrm{N}} 2$ mechanism.

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main
Wires 1 and 2 carrying currents $i_1$ and $i_2$ respectively are inclined at an angle $\theta$ to each other. What is the force on a small element dl of wire 2 at a distance of $\mathrm{r}$ from wire 1 (as shown in the figure) due to the magnetic field of wire 1 ?

Options:
A
$\frac{\mu_0}{2 \pi r} i_1 i_2 d l \tan \theta$

B
$\frac{\mu_0}{2 \pi \mathrm{r}} \mathrm{i}_1 \mathrm{i}_2 \mathrm{~dl} \sin \theta$

C
$\frac{\mu_0}{2 \pi \mathrm{r}} \mathrm{i}_1 \mathrm{i}_2 \mathrm{dl} \cos \theta$

D
$\frac{\mu_0}{4 \pi r} i_1 i_2 d l \sin \theta$

The correct answer is:
$\frac{\mu_0}{2 \pi \mathrm{r}} \mathrm{i}_1 \mathrm{i}_2 \mathrm{dl} \cos \theta$

Solution:
No Solution Available

Topic: Physics, Magnetic Effects of Current, JEE Main, JEE Main 2002
Wires $W_1$ and $W_2$ are made of same material having the breaking stress of $1.25 \times 10^9 \mathrm{~N} / \mathrm{m}^2$. $\mathrm{W}_1$ and $\mathrm{W}_2$ have cross-sectional area of $8 \times 10^{-7}$ $\mathrm{m}^2$ and $4 \times 10^{-7} \mathrm{~m}^2$, respectively. Masses of 20 $\mathrm{kg}$ and $10 \mathrm{~kg}$ hang from them as shown in the figure. The maximum mass that can be placed in the pan without breaking the wires is _______ kg. (Use $\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$)

Options:
A $40 \mathrm{~kg}$
B $60 \mathrm{~kg}$
C $80 \mathrm{~kg}$
D $20 \mathrm{~kg}$

The correct answer is:
$40 \mathrm{~kg}$

Solution:
$\begin{aligned} & \text { B. } S_1=\frac{T_{1 \max }}{8 \times 10^{-7}} \Rightarrow T_{1 \max }=8 \times 1.25 \times 100 \\ & =1000 \mathrm{~N} \\ & \text { B. } S_2=\frac{\mathrm{T}_{2 \max }}{4 \times 10^{-7}} \Rightarrow \mathrm{T}_{2 \max }=4 \times 1.25 \times 100 \\ & =500 \mathrm{~N} \\ & \mathrm{~m}=\frac{500-100}{10}=40 \mathrm{~kg}\end{aligned}$

Topic: Physics, Mechanical Properties of Solids, JEE Main
With an increase in temperature, surface tension of liquid (except molten copper and cadmium)

Options:
A increases
B remain same
C decreases
D first decreases then increases

The correct answer is:
decreases

Solution:
The surface tension of liquid decreases with rise of temperature. The surface tension of liquid is zero at its boiling point and it vanishes at critical temperature. $\quad$ At $\quad$ critical $\quad$ temperature intermolecular forces for liquid and gases becomes equal and liquid can expand without any restriction. For small temperature differences, the variation in surface tension with temperature is linear and is given by relation
$$
T_{t}=T_{0}(1-\alpha t)
$$
where $T_{t}, T_{0}$ are the surface tension at $t^{\circ} \mathrm{C}$ and $0^{\circ} \mathrm{C}$ respectively and $\alpha$ is the temperature coefficient of surface tension.

Topic: Physics, Thermal Properties of Matter, JEE Main
With an increase in temperature, surface tension of liquid (except molten copper and cadmium)

Options:
A increases
B remain same
C decreases
D first decreases then increases

The correct answer is:
decreases

Solution:
The surface tension of liquid decreases with rise of temperature. The surface tension of liquid is zero at its boiling point and it vanishes at critical temperature. $\quad$ At $\quad$ critical $\quad$ temperature intermolecular forces for liquid and gases becomes equal and liquid can expand without any restriction. For small temperature differences, the variation in surface tension with temperature is linear and is given by relation
$$
T_{t}=T_{0}(1-\alpha t)
$$
where $T_{t}, T_{0}$ are the surface tension at $t^{\circ} \mathrm{C}$ and $0^{\circ} \mathrm{C}$ respectively and $\alpha$ is the temperature coefficient of surface tension.

Topic: Physics, Thermal Properties of Matter, MHT CET, MHT CET 2010
With dehydrating agent present which dicarboxylic acid is least reactive towards forming an anhydride?

Options:
A

B

C

D

The correct answer is:

Solution:
7 member cyclic anhydide is less stable.

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main, JEE Main 2019 (10 Jan Shift 1)
With excess bromine, phenol reacts of form

Options:
A

B

C

D Mixture of (a) and (b)

The correct answer is:

Solution:

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
With increase in frequency of a.c. supply, the impedance of an $\mathrm{L}-\mathrm{C}$-R series circuit

Options:
A remains constant.
B increases.
C decreases.
D decreases at first, becomes minimum and then increases.

The correct answer is:
decreases at first, becomes minimum and then increases.

Solution:
We know
$\mathrm{X}_{\mathrm{L}}=\mathrm{L} \omega$ and $\mathrm{X}_{\mathrm{C}}=\frac{1}{\mathrm{C} \omega}$
$\Rightarrow$ When the frequency increases, $X_{\mathrm{L}}^{\prime}$ increases and $X_c$ decreases.
$\therefore \quad$ The impédance of an LCR series circuit decreases at first, becomes minimum and then increases.

Topic: Physics, Alternating Current, MHT CET, MHT CET 2023 (13 May Shift 1)
With increase in temperature, the magnetic susceptibility of a ferromagnetic material will

Options:
A increase
B decrease
C increase initially and then decrease
D remain constant

The correct answer is:
decrease

Solution:
Magnetic susceptibility is a dimensionless proportionality constant that indicates the degree of magnetization of a material in response to an applied magnetic field.
And the relation between Magnetic susceptibility and Temperature can be given as
$\chi=\frac{O}{T-T_0}$

Topic: Physics, Magnetic Properties of Matter, JEE Main
With increase in temperature, the viscosity of

Options:
A
gases decreases

B
liquids increases

C
gases increases

D
liquids decreases

The correct answers are:
gases increases
,
liquids decreases

Solution:
As we know that,
For liquids coefficient of viscosity,
$\eta \propto \frac{1}{\sqrt{T}}$
As increase in temperature, the KE of fluid increases, and layers speed increases but relative speed of layer remain same.
For gases coefficient of viscosity, $\eta \propto \sqrt{T}$
As increase in temperature, the KE of gas molecule increases and hence collision increases the viscosity.

Topic: Physics, Mechanical Properties of Fluids
With increase in temperature what happens to fractions of molecules having Vmp?

Options:
A Increase
B Remains same
C Decrease
D None of the above

The correct answer is:
Decrease

Solution:
Correct Option is : 3
Decrease

Topic: Chemistry, Chemical Kinetics, NEET
With increase in temperature what happens to Vmp?

Options:
A Decrease
B Increase
C Remains same
D None of the above

The correct answer is:
Increase

Solution:
Correct Option is : 2
Increase

Topic: Chemistry, Chemical Kinetics, NEET
With increase of temperature, which of these changes?

Options:
A
molality

B
weight fraction of solute

C
fraction of solute present in water

D
mole fraction

The correct answer is:
fraction of solute present in water

Solution:
Volume increases with rise in temperature.

Topic: Chemistry, Solutions, JEE Main, JEE Main 2002
With increasing biasing voltage of a photo diode, the photocurrent magnitude:

Options:
A remains constant
B increases initially and after attaining certain value, it decreases
C increases linearly
D increases initially and saturates finally

The correct answer is:
increases initially and saturates finally

Solution:
The photocurrent magnitude increases initially and saturates finally.

Topic: Physics, Semiconductors, JEE Main, JEE Main 2020 (05 Sep Shift 1)
With increasing Principal Quantum number, the energy difference between adjacent energy levels in H-atom

Options:
A Decreases
B Increases
C remain constant
D decreases at low level of ' n ' \& increases for higher value of ' n '

The correct answer is:
Decreases

Solution:
Therefore the energy difference between n1&n2 energy level,

Energy formula for the hydrogen atom is :-

∆E=En2-En1=13.6Z21n12-1n22

∆E∝ 1n12-1n22

n1&n2= principle quantum Number

∵∆E∝ 1n12-1n22 so when n1&n2 increases

∆Edecreases.

Change in energy is inversely proportional to the increase in the principle quantum number.

Hence, with increasing Principal Quantum number, the energy difference between adjacent energy levels in H-atom decreases.

Topic: Chemistry, Structure of Atom, AP EAMCET, AP EAMCET 2021 (20 Aug Shift 2)
With reference to the observations in photo-electric effect, identify the correct statements from below:

A. The square of maximum velocity of photoelectrons varies linearly with frequency of incident light.

B. The value of saturation current increases on moving the source of light away from the metal surface.

C. The maximum kinetic energy of photo-electrons decreases on decreasing the power of LED (light emitting diode) source of light.

D. The immediate emission of photo-electrons out of metal surface can not be explained by particle nature of light/electromagnetic waves.
E. Existence of threshold wavelength can not be explained by wave nature of light/electromagnetic waves.

Choose the correct answer from the options given below:

Options:
A A and B only
B A and E only
C C and E only
D D and E only

The correct answer is:
A and E only

Solution:
From Einstein's photoelectric equation,

Maximum kinetic energy, KEmax=12mvmax2=hf-ϕ, where, vmax is maximum velocity of photoelectrons, h is Planck's constant, f is frequency of incident light and ϕ is work function of metal.

From above relation, we can see that the square of maximum velocity of photoelectrons varies linearly with frequency of incident light.

If we increase the intensity of the incident radiation by keeping the frequency constant, then the value of saturation current increases in proportion to the intensity of the incident radiation. Thus, saturation current decreases on moving the source of light away from the metal surface.

The kinetic energy of the photoelectrons is directly proportional to the light frequency, and it remains constant as light amplitude or power of source increases.

Photoelectric effect cannot be explained on the basis of wave nature because experimentally a particular energy called the work function of the metal surface in needed to eject electrons from surface, irrespective of the time for which light is incident.

Photoelectric effect can be explained by particle nature of light (i.e. quantum theory). Threshold wavelength is maximum wavelength at which emission takes place.

Topic: Physics, Dual Nature of Matter, JEE Main, JEE Main 2022 (27 Jul Shift 2)
With respect to air, the critical angle in a medium for red light of wave length $\lambda_1$ is $\theta$. Other facts remaining same, critical angle for yellow light of wave length $\lambda_2$ will be

Options:
A $\theta$
B more than $\theta$
C less than $\theta$
D $\frac{\theta \lambda_1}{\lambda_2}$

The correct answer is:
less than $\theta$

Solution:
Critical angle $=\sin ^{-1}\left(\frac{1}{\mathrm{n}}\right)=\sin ^{-1}\left(\frac{\mathrm{v}}{\mathrm{c}}\right)$
Critical angle $=\sin ^{-1}\left(\frac{\mathrm{f} \lambda}{\mathrm{c}}\right) \quad\left(\because \mathrm{v}=\frac{\mathrm{c}}{\mathrm{n}}\right)$
for red light, $\theta=\sin ^{-1}\left(\frac{f \lambda_1}{c}\right)(\because v=f \lambda)$
for yellow light $\theta^{\prime}=\sin ^{-1}\left(\frac{\mathrm{f} \lambda_2}{\mathrm{c}}\right)$
Since $\lambda_1>\lambda_2$
then $\theta^{\prime} < \theta$

Topic: Physics, Ray Optics, AP EAMCET, AP EAMCET 2023 (19 May Shift 1)
With respect to graphite and diamond, which of the statement (s) given below is (are) correct?
1. Graphite has higher electrical conductivity than diamond
2. Graphite is harder than diamond
3. Graphite has higher C - C bond order than diamond
4. Graphite has higher thermal conductivity than diamond

Options:
A 1,2
B 1,2,3
C 1,3,4
D 2,3,4

The correct answer is:
1,3,4

Solution:
Here 1, 3 and 4 are correct as Graphite has higher electrical and thermal conductivities than diamond.
All C- atoms in graphite are sp2 hybridised so due to partial double bond character in graphite, bond order will be more than 1 but in diamond Bond order is one.
Here only statement 2 is incorrect as diamond is more hard than graphite.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
With respect to In-situ conservation, the conservation of national genetic resources can be achieved by establishing

Options:
A National park
B Wild life sanctuaries
C Biosphere reserve
D All of the above

The correct answer is:
All of the above

Solution:
In-situ conservation is the process of conserving biodiversity, where all living species, mainly the wild and endangered species, are saved in their natural habitat and environment. This includes biosphere reserves, national parks, wildlife sanctuaries, etc.

Topic: Biology, Biodiversity and its Conservation, NEET
With respect to the conformers of ethane, which of the following statements is true?

Options:
A Bond angle remains the same but bond length changes.
B Bond angle changes but bond length remains the same.
C Both bond angle and bond length changes.
D Both bond angles and bond length remains the same.

The correct answer is:
Both bond angles and bond length remains the same.

Solution:
There is no change in bond angles and bond lengths in the conformations of ethane. There is only change in dihedral angle.

Topic: Chemistry, General Organic Chemistry, NEET, NEET 2017
With respect to the conformers of ethane, which of the following statements is true?

Options:
A Bond angle changes but bond length remains same
B Both bond angle and bond length change
C Both bond angles and bond length remains same
D Bond angle remains same but bond length changes

The correct answer is:
Both bond angles and bond length remains same

Solution:
Conformers of ethane have different dihedral angles andthere is no change in bond angles and bond lengths in the conformations of ethane.

Topic: Chemistry, General Organic Chemistry, NEET
With respect to the sodium-potassium pump, what changes will be observed when one molecule of ATP is used during the process?

Options:
A 3 ions of Na+ are pumped out and 2K+ are taken in
B 3 ions of Na+ are taken in and 2K+ are pumped out
C 2 ions of Na+ are thrown out and 3K+ are absorbed
D 3 ions of K+ are absorbed, 3Na+ are pumped out

The correct answer is:
3 ions of Na+ are pumped out and 2K+ are taken in

Solution:
Energy from ATP causes a conformational change in the solute carrier complex. The process of moving sodium and potassium ions across the cell membrane is an active transport process involving the hydrolysis of ATP to provide the necessary energy. This process is responsible for maintaining the large excess of Na+ outside the cell and the large excess of K+ ions on the inside. This accomplishes the transport of three Na+ to the outside of the cell and the transport of the two K+ ions to the inside. This unbalanced charge transfer contributes to the separation of the charge across the membrane. The sodium-potassium pump is an important contributor to the action potential produced by the nerve cells.

Topic: Biology, Neural Control and Coordination, NEET
With rise in temperature, the Young's modulus of elasticity

Options:
A changes erratically
B decreases
C increases
D remains unchanged

The correct answer is:
decreases

Solution:
With rise in temperature, Young’s modulus of elasticity decreases due to the increase in atomic
vibrations which leads to decrease in atomic forces. The Young's modulus is a measure of stiffness of the material. With rise in temperature, the length of the material increases which decreases its stiffness.

Topic: Physics, Mechanical Properties of Solids, JEE Main, JEE Main 2024 (01 Feb Shift 1)