datavorous/entrance-exam-dataset huggingface dataset:
Which of the following statements is true about \( \mathrm{Ca}(\mathrm{OH})_{2} \) ?

Options:
A It is used in the preparation of bleaching powder.
B It is a light blue solid.
C It does not possess disinfectant property.
D It is used in the manufacture of cement.

The correct answer is:
It is used in the preparation of bleaching powder.

Solution:
Calcium hydroxide reacts with chlorine to form calcium hypochlorite, which is a component of bleaching powder.

The reaction is as follows:

2CaOH2+2Cl2→CaOCl2+CaCl2+2H2O

Topic: Chemistry, s Block Elements, JEE Main
Which of the following statements is true for all the alkali metals?

Options:
A Their nitrates decomposes on heating to give the corresponding nitrites and oxygen
B Their chlorides are deliquescent and crystallize as hydrates.
C They react with water to form hydroxide and hydrogen.
D They react with halogens to form only ionic halides M+X- .

The correct answer is:
They react with water to form hydroxide and hydrogen.

Solution:
A  4  LiNO 3 →2  Li 2 O + 4  NO 2  +  O 2
2  NaNO 3 →2  NaNO 2 + O 2 similar decomposition with the nitrates of K, Pb and Cs )
B Only LiCl is deliquescent and crystallises as a hydrate LiCl . 2H2O
C  2 M+2  H 2 O→2  M + +2  OH − + H 2 (M is an alkali metal)
D Halides of Li are covalent in nature.

Topic: Chemistry, Solutions, JEE Main
Which of the following statements is true for fuel cells

Options:
A They are more efficient
B They are free from pollution
C They run till reactants are active
D All of these

The correct answer is:
All of these

Solution:
Fuel cells are more efficient as they are free from pollution and hence they run till the reactants are active. They have longer life than lead storage cells

Topic: Chemistry, Electrochemistry, JEE Main
Which of the following statements is true for pollination by water?

Options:
A Pollen grains of water pollinated plants are small and spherical.
B The flowers of water pollinated plants are not very colourful.
C Female flowers of Vallisneria remain submerged in water and male flowers release the pollen inside the water causing pollination deep within water.
D Nelumbo nucifera (Indian lotus) is an aquatic plant pollinated by water.

The correct answer is:
The flowers of water pollinated plants are not very colourful.

Solution:
Pollen grains of water pollinated plants are long and ribbon like.
Flowers of water pollinated plants are not colorful or produce much nectar as they do not need to attract insects or birds for pollination. The female flowers of Vallisneria, a fresh water plant, reach the surface of water by a long stalk and make gametes are also released on the surface. Nelumbo nucifera (Indian lotus) is an aquatic plant pollinated by insects.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
Which of the following statements is true for the reaction given below?

Options:
A P is a the meso compound 2, 3-butanediol formed by syn-addition
B P is a the meso compound 2, 3-butanediol formed by anti-addition
C P is a racemic mixture of (d) and (I) 2, 3-butanediol formed by anti-addition
D P is a racemic mixture of (d) and (I) 2, 3-butanediol formed by syn-addition

The correct answer is:
P is a the meso compound 2, 3-butanediol formed by syn-addition

Solution:
Cis-2-butene undergoes hydroxylation by syn-addition forming meso product.

Topic: Chemistry, Hydrocarbons, JEE Main
Which of the following statements is true in case of the principle of perpendicular axes?

Options:
A It is applicable to only three dimensional objects.
B It is applicable to planar as well as three dimensional objects.
C It is applicable to only planar objects.
D It is applicable to only denser objects.

The correct answer is:
It is applicable to only planar objects.

Solution:
Perpendicular axes theorem is applicable of two dimensional bodies or planer bodies having almost negligible thickness.

From figure the moment of inertia about rotational axis (Z-axis) which is normal to plane of body is given by

IZ=IX+IY

Where Ix,Iy are moment of inertia of body about two mutually perpendicular axes in the plane of body.

Above theorem is not applicable for three-dimensional bodies.

Topic: Physics, Rotational Motion, JEE Main
Which of the following statements is true regarding the solubility of phenols in water?

Options:
A Solubility increases with the size of the alkyl groups.
B Solubility decreases as the number of hydroxyl groups increases.
C Solubility decreases with increased branching in the phenolic ring.
D Solubility remains constant regardless of structural modifications.

The correct answer is:
Solubility decreases with increased branching in the phenolic ring.

Solution:
Increased branching in the phenolic ring reduces the availability of -OH groups for hydrogen bonding with water, decreasing solubility.

Topic: Chemistry, Alcohols Phenols and Ethers, NEET
Which of the following statements is true/correct?

Options:
A During clear nights, the temperature rises steadily upward near the ground level
B Newton's law of cooling, an approximate form of Stefan's law, is valid only for natural convection
C The total energy emitted by a black body per unit time per unit area is proportional to the square of its temperature in the Kelvin scale
D Two spheres of the same material have radii $1 \mathrm{~m}$ and $4 \mathrm{~m}$ and temperatures $4000 \mathrm{~K}$ and $2000 \mathrm{~K}$ respectively. The energy radiated per second by the first sphere is greater than that radiated per second by the second sphere

The correct answer is:
Newton's law of cooling, an approximate form of Stefan's law, is valid only for natural convection

Solution:
During clear nights object on surface of earth radiate out heat and temperature falls. Hence option (a) is wrong. The total energy radiated by a body per unit time per unit area $E \propto T^{4}$. Hence option (c) is
wrong. Energy radiated per second is given by
$\begin{aligned} \frac{Q}{t} &=P A \varepsilon \sigma T^{4} \\ \Rightarrow \quad \frac{P_{1}}{P_{2}} &=\frac{A_{1}}{A_{2}}\left(\frac{T_{1}}{T_{2}}\right)^{4}=\left(\frac{\pi}{r_{2}}\right)^{2} \cdot\left(\frac{T_{1}}{T_{2}}\right)^{4} \\ &=\left(\frac{1}{4}\right)^{2}\left(\frac{4000}{200}\right)=\frac{1}{1} \end{aligned}$
$\because P_{1}=P_{2}$, hence option (d) is wrong. Newton's law is an approximate from of Stefan's law of radiation and works well for natural convection. Hence option (b) is correct.

Topic: Physics, Thermal Properties of Matter, JEE Main
Which of the following statements is wrong?

Options:
A
Ethyl chloride on reduction with $\mathrm{Zn}-\mathrm{Cu}$ couple and alcohol gives ethane.

B
The reaction of methyl magnesium bromide with acetone gives butanol-2.

C
Alkyl halides follow the following reactivity sequence on reaction with alkenes.
$$
\mathrm{R}-\mathrm{I}>\mathrm{R}-\mathrm{Br}>\mathrm{R}-\mathrm{Cl}>\mathrm{R}-\mathrm{I}
$$

D
$\mathrm{C}_2 \mathrm{H}_4 \mathrm{Cl}_2$ may exist in two isomeric forms

The correct answer is:
The reaction of methyl magnesium bromide with acetone gives butanol-2.

Solution:

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main, JEE Main 2012 (12 May Online)
Which of the following statement(s) is/are correct?

(A) The pH of 1×10–8 M HCl solution is 8.

(B) The conjugate base of H2PO4- is HPO42-.

(C) Kw increases with increase in temperature.

(D) When a solution of a weak monoprotic acid is titrated against a strong base at half neutralisation point, pH=12pKa. Choose the correct answer from the options given below:

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

The correct answer is:
B, C

Solution:
When concentration of H+ ion is more than 10-7M, the proton concentration from water must be considered. Hence, the pH of 10-8M HCl solution is not equal to 8.

H2PO4-Acid⇌HPO42-Conjugate base+H+

Kw increase with increase in temperature as dissociation of water increases with increase in temperature.

When weak monoprotic acid is titrated against strong base, at half neutralization point, the solution becomes acidic buffer and its pH is given by

pH=pKa+logSaltAcid

⇒pH=pKa+0 as salt=acid

Topic: Chemistry, Ionic Equilibrium, JEE Main
Which of the following statement(s) is/are correct?

(A) The pH of 1×10–8 M HCl solution is 8.

(B) The conjugate base of H2PO4- is HPO42-.

(C) Kw increases with increase in temperature.

(D) When a solution of a weak monoprotic acid is titrated against a strong base at half neutralisation point, pH=12pKa. Choose the correct answer from the options given below:

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

The correct answer is:
B, C

Solution:
When concentration of H+ ion is more than 10-7M, the proton concentration from water must be considered. Hence, the pH of 10-8M HCl solution is not equal to 8.

H2PO4-Acid⇌HPO42-Conjugate base+H+

Kw increase with increase in temperature as dissociation of water increases with increase in temperature.

When weak monoprotic acid is titrated against strong base, at half neutralization point, the solution becomes acidic buffer and its pH is given by

pH=pKa+logSaltAcid

⇒pH=pKa+0 as salt=acid

Topic: Chemistry, Ionic Equilibrium, JEE Main, JEE Main 2023 (15 Apr Shift 1)
Which of the following statements is/are false?

Options:
A Na2Cr2O7 is more soluble than K2Cr2O7.
B CrO42- is tetrahedral in shape.
C Na2Cr2O7 is the primary standard in volumetry.
D Cr2O72- has a Cr-O-Cr bond.

The correct answer is:
Na2Cr2O7 is the primary standard in volumetry.

Solution:
It is true Na 2 Cr 2 O 7 is more soluble than K 2 Cr 2 O 7 .
CrO 4 −2 Is tetrahedral:

Na2Cr2O7 is not the primary standard but K2Cr2O7 (acidic) is the primary standard reagent for titration because sodium dichromate is Hygroscopic in nature, that means it absorb moisture from atmosphere, that will cause incorrect reading in titration.

Topic: Chemistry, d and f Block Elements, JEE Main, JEE Main 2015 (11 Apr Online)
Which of the following statements is/are true?
1.$\mathrm{PH}_{5}$ and $\mathrm{BiCl}_{5}$ do not exist.
2.$p \pi-d \pi$ bond is present in $\mathrm{SO}_{2}$
3.$\mathrm{I}_{3}^{+}$ has bent geometry.
4.$\mathrm{SeF}_{4}$ and $\mathrm{CH}_{4}$, have same shape.

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

The correct answer is:
1,2,3

Solution:
All the three statements are correct.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
Which of the following statements regarding boric acid is false -

Options:
A It acts as a tribasic acid
B It has a planar structure
C It acts as a monobasic acid
D It is soluble in hot water

The correct answer is:
It acts as a tribasic acid

Solution:
A Boric acid H3BO3 is a lewis acid,when it is dissolved in water, it accepts OH- from water rather than donating H+ to the water. So, A it is false.
B It has a planar structure.
C It acts as a monobasic acid: B(OHâ¡)3+H2OâB(OHâ¡)4-+H+
D It is soluble in hot water.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Which of the following statements regarding centre of mass is NOT true?

Options:
A For two particles of equal mass, the centre of mass lies exactly midway between them
B For three non-linear particles of equal mass, the centre of mass coincides with the centroid of the triangle formed by the particles
C When the total external force on a system is zero, the velocity of the centre of mass of the system remains constant.
D For two particles of different masses, the centre of mass of the particles is nearer to the particle of lesser mass.

The correct answer is:
For two particles of different masses, the centre of mass of the particles is nearer to the particle of lesser mass.

Solution:
Option (d) is incorrect because the centre of mass o two particles is nearer to the particle of higher mas not lesser mass.

Topic: Physics, Center of Mass Momentum and Collision, AP EAMCET, AP EAMCET 2023 (18 May Shift 1)
Which of the following statements regarding definite integration is true for $f(x)$ defined on the interval $[a, b]$ ?

Options:
A If $f(x)$ is non-negative on $[a, b]$, then $\int_a^b f(x) d x$ is non-negative.
B If $f(x)$ is non-positive on $[a, b]$, then $\int_a^b f(x) d x$ is non-negative.
C If $f(x)$ is non-negative on $[a, b]$, then $\int_a^b f(x) d x$ is negative.
D If $f(x)$ is non-positive on $[a, b]$, then $\int_a^b f(x) d x$ is positive.

The correct answer is:
If $f(x)$ is non-negative on $[a, b]$, then $\int_a^b f(x) d x$ is non-negative.

Solution:
1) Correct. By the property of definite integration, if $f(x)$ is non-negative on $[a, b]$, then the area under the curve will be non-negative as well.
2) Incorrect. If $f(x)$ is non-positive, the integral will be non-positive or zero, not necessarily nonnegative.
3) Incorrect. If $f(x)$ is non-negative, the integral will be non-negative or zero, not negative.
4) Incorrect. If $f(x)$ is non-positive, the integral will be non-positive or zero, not necessarily positive.

Topic: Mathematics, Definite Integration, JEE Main
Which of the following statements regarding digestive glands is correct?

Options:
A Saliva is produced mainly by three glands in the human body.
B The liver is situated in the abdominal cavity, just lateral to the diaphragm.
C The common hepato-pancreatic duct is guarded by the sphincter of Oddi.
D The exocrine portion of the pancreas secretes an acidic pancreatic juice.

The correct answer is:
The common hepato-pancreatic duct is guarded by the sphincter of Oddi.

Solution:
Saliva is produced by three pairs of glands, i.e., parotid, sub-mandibular and sublingual glands. The liver is situated in the abdominal cavity just above the diaphragm. The exocrine portion of the pancreas secretes pancreatic juice, which is alkaline in nature.

Topic: Biology, Digestion and Absorption, NEET
Which of the following statements regarding fertilization is/are correct?

(i) The acrosome is filled with hydrolytic enzymes which help in dissolving the membrane of the ovum at the time of fertilization.

(ii) Vitelline membrane is the first membrane to be faced by sperms while trying to fuse with the ovum.

(iii) There must be synchronicity in the release of ovum and entry of sperm for the formation of zygote.

(iv) The meiotic division of the secondary oocyte is concluded with the entry of male gamete.

Options:
A i and ii only
B ii and iii only
C i, iii and iv
D i, ii and iv

The correct answer is:
i, iii and iv

Solution:
During fertilization for the entry of sperm in the ovum, the acrosome breaks it with the help of digestive enzymes present in it. The acrosome contains hyaluronidase and acrosin enzymes which eat up the zona pellucida and allows the haploid nucleus in the sperm to join with the haploid nucleus of the ovum.
The outer membrane of the ovum is called Zona pellucida.
Egg can only survive for up to 24 hours after it's released while sperm can live in the female reproductive tract for about 3 to 5 days. Meeting of sperm with ovum in this duration can increase the chances of fertilization.
In oogenesis, oogonium(2n) undergoes mitosis and develops into a primary oocyte, which will begin the first meiotic division, but then arrest; it will finish this division as it develops in the follicle, giving rise to a haploid secondary oocyte and a smaller polar body.
The secondary oocyte begins the second meiotic division and then arrests again; and will remain so unless it is fertilized by a sperm; if this occurs, a mature ovum and another polar body is produced.

Topic: Biology, Human Reproduction, NEET
Which of the following statements regarding ozone is not correct?

Options:
A The Ozone molecule is angular in shape
B The Ozone is a resonance hybrid of two structures
C The Oxygen-Oxygen bond length in ozone is identical with that of molecular oxygen
D Ozone is used as germicide and disinfectant for the purification of air.

The correct answer is:
The Oxygen-Oxygen bond length in ozone is identical with that of molecular oxygen

Solution:
Hints : Due to resonance the bond order in ozone is 1.5 , hence $\mathrm{O}-\mathrm{O}$ bond length in $\mathrm{O}_3>\mathrm{O}-\mathrm{O}$ bond length in $\mathrm{O}_2$

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following statements regarding species interdependence are true?

I. An association of two species where one is benefitted and other remains unaffected is called mutualism.
II. An interspecific association where both partners derive benefit from each other is called commensalism.
III. A direct food relation between two species of animals in which one animal kills and feeds on another is referred to as predation.
IV. A relationship between two species of organisms where both the partners are benefitted from each other is called symbiosis.

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

The correct answer is:
III and IV only

Solution:
Predation is a direct food relation between two species of animals, in which one animal (the predator) captures and feeds on another (the prey).
In symbiosis, two organisms live together in close physical association from which one or both derive benefit.
Mutualism: It confers benefits on both the interacting species. It is an obligate association of two organisms where two organisms often live together and cannot live separately.
Commensalism is the interaction in which one species benefits and other is neither harmed nor benefited. The species which is benefitted is termed commensal and the other species is called host.

Topic: Biology, Organisms and Populations, NEET
Which of the following statements regarding sulphur is incorrect?

Options:
A
The vapour at $200^{\circ} \mathrm{C}$ consists mostly of $\mathrm{S}_8$ rings

B
At $600^{\circ} \mathrm{C}$ the gas mainly consists of $\mathrm{S}_2$ molecules

C
The oxidation state of sulphur is never less than $+4$ in its compounds

D
$\mathrm{S}_2$ molecule is paramagnetic.

The correct answer is:
The oxidation state of sulphur is never less than $+4$ in its compounds

Solution:
'S' can exhibit a minimum oxidation state of $-2$
(Ex. $\mathrm{H}_2 \mathrm{~S}$ )

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main, JEE Main 2011
Which of the following statements regarding sulphur is not correct?

Options:
A At about $1000 \mathrm{~K}$, it mainly consists of $\mathrm{S}_2$ molecules
B The oxidation state of sulphur is never less than + 4 in its compounds
C $S_2$ molecule is paramagnetic
D Rhombic sulphur is readily soluble in $CS_2$

The correct answer is:
At about $1000 \mathrm{~K}$, it mainly consists of $\mathrm{S}_2$ molecules

Solution:
At high temperature about $1000 \mathrm{k}$, sulphur consists of mixture of forms $\mathrm{S}_2, \mathrm{~S}_4, \mathrm{~S}_6, \mathrm{~S}_8$, etc.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), AP EAMCET, AP EAMCET 2016
Which of the following statements regarding the first law of thermodynamics is correct?

Options:
A The energy of the isolated system plus the energy of the surrounding is constant.
B The energy of the isolated system minus the energy of the surrounding is constant.
C The energy of an isolated system is constant.
D The energy of an isolated system varies.

The correct answer is:
The energy of an isolated system is constant.

Solution:
(c) $\because$ According to first law of thermodynamics, the total energy of an isolated system remains constant, through it may change from one form to another.

Topic: Chemistry, Thermodynamics (C), TS EAMCET, TS EAMCET 2020 (11 Sep Shift 2)
Which of the following statements regarding the structure of $\mathrm{SOCl}_2$ is not correct?

Options:
A The sulphur is $\mathrm{sp}^3$ hybridised and it has a tetrahedral shape.
B The sulphur is $\mathrm{sp}^3$ hybridised and it has a trigonal pyramid shape.
C The oxygen-sulphur bond is $\mathrm{p} \pi-\mathrm{d} \pi$ bond.
D It contain one lone pair of electrons in the $\mathrm{sp}^3$ hybrid orbital of sulphur.

The correct answer is:
The sulphur is $\mathrm{sp}^3$ hybridised and it has a tetrahedral shape.

Solution:
in $\mathrm{SOCl}_2$, sulphur atom is $\mathrm{sp}^{3}$ hybridised. Due to the presence of one lone pair of electrons on ' $\mathrm{S}$ ' atom, the molecule has distorted tetrahedral shape. i.e., trigonal pyramidal shape. This shape contains two chlorine and one oxygen atom in a triangle. The $\mathrm{S}-\mathrm{O}-\mathrm{pi}$ bond is $\mathrm{d} \pi-\mathrm{p} \pi$ pi bond.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
Which of the following statements will be surely CORRECT about a vertebrate that has a complete four-chambered heart?

I. The animal shows pulmonary respiration.
II. The animal has double circulation.
III. The animal has left systemic arch (aorta curved to left).
IV. The animal can maintain constant body temperature.

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

The correct answer is:
I and II

Solution:
Birds and Mammals have 4 chambered heart. Organisms of both of these groups respire through lungs, have double circulation and can maintain constant body temperature. Birds have a right systemic arch and mammals have a left systemic arch. Crocodiles which are reptiles also have a four-chambered heart but they can't maintain a constant body temperature.

Topic: Biology, Animal Kingdom, NEET
Which of the following statements/relationships is not correct in thermodynamic changes ?

Options:
A
$\Delta \mathrm{U}=0$ (isothermal reversible expansion of a gas)

B
$\mathrm{w}=-\mathrm{nRT} \ln \frac{\mathrm{V}_2}{\mathrm{~V}_1}$ (isothermal reversible expansion of an ideal gas)

C
$\mathrm{w}=\mathrm{nRT} \ln \frac{\mathrm{V}_2}{\mathrm{~V}_1}$ (isothermal reversible expansion of an ideal gas)

D
For a system of constant volume heat involved directly changes to internal energy.

The correct answer is:
$\mathrm{w}=\mathrm{nRT} \ln \frac{\mathrm{V}_2}{\mathrm{~V}_1}$ (isothermal reversible expansion of an ideal gas)

Solution:
For isothermal reversible expansion.
$$
w=-n R T \ln \frac{V_2}{V_1}
$$

Topic: Chemistry, Thermodynamics (C), JEE Main, JEE Main 2013 (23 Apr Online)
Which of the following statements(s) is/are true? "Internal energy of an ideal gas ..........."

Options:
A decreases in an isothermal process.
B remains constant in an isothermal process.
C increases in an isobaric process.
D decreases in an isobaric expansion.

The correct answers are:
remains constant in an isothermal process.

Solution:
$\because$ Internal energy of an ideal gas depends only on the temperature of gas.
$$
E_{\text {in }} \propto T
$$

Topic: Physics, Thermodynamics, WBJEE, WBJEE 2018
Which of the following steps is NOT part of finding orthogonal trajectories of a given family of curves?

Options:
A Find the differential equation representing the given family of curves.
B Replace $\frac{d y}{d x}$ with $-\frac{d x}{d y}$ in the differential equation.
C Integrate the resulting differential equation to find the orthogonal trajectories.
D Replace the variables $x$ and $y$ with $u$ and $v$ respectively.

The correct answer is:
Replace the variables $x$ and $y$ with $u$ and $v$ respectively.

Solution:
Replace the variables $x$ and $y$ with $u$ and $v$ respectively.
Explanation:
To find orthogonal trajectories, we need to first find the differential equation of the given family of curves, replace $\frac{d y}{d x}$ with $-\frac{d x}{d y}$ to account for the perpendicular slopes, and then integrate the resulting differential equation. Replacing $x$ and $y$ with $u$ and $v$ is not a necessary step in this process.

Topic: Mathematics, Differential Equations, JEE Main