datavorous/entrance-exam-dataset huggingface dataset:
$\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3$ (at. no. or $\mathrm{Cr}=24$ ) has a magnetic moment of 3.83 B.M. The correct distribution of $3 d$ electrons in the Chromium of the complex is:

Options:
A \(\left(3 \mathrm{~d} \mathrm{x}^2-\mathrm{y}^2\right)^1, 3 \mathrm{~d} \mathrm{z}^{2^1}, 3 \mathrm{dxz}\)
B \(3 \mathrm{~d} \mathrm{xy}^1,\left(3 \mathrm{~d} x^2-y^2\right)^1, 3 \mathrm{~d} y z^1\)
C \(3 \mathrm{~d} x y^1, 3 \mathrm{~d} y z^1, 3 \mathrm{~d} x z^1\)
D \(3 \mathrm{~d} \mathrm{xy}^1, 3 \mathrm{dyz}{ }^1, 3 d z^{2^{\prime}}\)

The correct answer is:
\(3 \mathrm{~d} \mathrm{xy}^1, 3 \mathrm{dyz}{ }^1, 3 d z^{2^{\prime}}\)

Solution:
Magnetic moment
$$
\begin{aligned}
(\mu) & =\sqrt{n(n+2)} \mathrm{BM} \\
3.83 & =\sqrt{n(n+2)} \\
3.83 \times 3.83 & =n^2+2 n \\
14.6689 & =n^2+2 n
\end{aligned}
$$
On solving this, we get $n=3$.
Hence, the number of unpaired electrons in the $d$-subshell of the penultimate shell of chromium is 3 .
So,
$\mathrm{Cr}^{3+}=1 s^2, 2 s^2 2 p^6, 3 s^2 3 p^2 3 d^3$
In $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3$, the oxidation state of $\mathrm{Cr}$ is +3 .
Hence, in $3 d^3$, the distribution of
electrons is $3 d_{x y}^1, 3 d^1, 3 d^1{ }_{x x^*}$

Topic: Chemistry, Coordination Compounds, NEET, NEET 2006
Creating awareness about sex related aspects is an effective method to improve the reproductive health of the people.

Options:
A True
B False
C Maybe
D Cannot be defined.

The correct answer is:
True

Solution:
Creating awareness about sex related aspects is an effective method to improve the reproductive health of the people.

Topic: Biology, Reproductive Health, NEET
Cretinism is caused due to:

Options:
A Low GH from pituitary gland
B Excessive glucocorticoids from adrenal glands
C Low secretion of parathyroid hormone
D Low secretion of thyroid hormones from thyroid gland

The correct answer is:
Low secretion of thyroid hormones from thyroid gland

Solution:
Hypothyroidism that is low thyroid hormone levels during pregnancy causes defective development and maturation of the growing baby leading to stunted growth (cretinism), mental retardation, low intelligence quotient, abnormal skin, deaf-mutism.

Topic: Biology, Chemical Coordination and Integration, NEET
Cretinism is due to

Options:
A hyposecretion of thyroxine in adult
B hypersecretion of thyroxine in childhood
C Hypersecretion of thyroid in adult
D Hyposecretion of thyroxine in childhood

The correct answer is:
Hyposecretion of thyroxine in childhood

Solution:
Hyposecretion of thyroxine during the growth years or birth or in childhood results in hypothyroidism or cretinism. Two important symptoms are dwarfism and mental retardation.

Topic: Biology, Chemical Coordination and Integration, NEET
Cri-du-chat syndrome in humans is caused by the:

Options:
A trisomy of $21^{\text {st }}$ chromosome
B fertilization of an XX egg by a normal Y-bearing sperm
C loss of half of the short arm of chromosome 5
D loss of half of the long arm of chromosome 5

The correct answer is:
loss of half of the short arm of chromosome 5

Solution:
Cri-du-chat (cat's cry) syndrome, also known as 5p- (5p minus) syndrome is caused by a partial deletion (monosomy) of a varying length of the short arm (p) of chromosome 5. Infants with this condition often have a high-pitched cry that sounds like that of a cat. Down syndrome occurs due to trisomy of $21^{\text {st }}$ chromosome. Klinefelter syndrome is a genetic condition that results when a boy is born with an extra copy of the $\mathrm{X}$ chromosome.

Topic: Biology, Principles of Inheritance and Variation, NEET, NEET 2006
Crimson red is emitted by which of the following elements during flame test?

Options:
A Cs
B Rb
C Na
D Li

The correct answer is:
Cs

Solution:
Correct Option is : 1
Cs

Topic: Chemistry, s Block Elements, NEET
Critical temperatures for carbon dioxide and methane are 31.1°C and –81.9°C respectively. Which of these has stronger intermolecular forces and why?

Options:
A Both have same intermolecular forces
B Methane
C Carbon Dioxide
D Cannot be discussed without further information

The correct answer is:
Carbon Dioxide

Solution:
Correct Option is : (C)
Carbon Dioxide

Topic: Chemistry, States of Matter, NEET
CrO 4 2 - (yellow) changes to Cr 2 O 7 2 - (orange) in pH = x and vice - versa in pH= y. Hence, x and y may be-

Options:
A 5, 9
B 6, 5
C 8, 6
D 7, 7

The correct answer is:
5, 9

Solution:
2 CrO 4 2 - + 2 H + ⟶ Cr 2 O 7 2 - + H 2 O [where x= pH = 4 - 5]
Cr 2 O 7 2 - + 2 OH - ⟶ 2 CrO 4 2 - + H 2 O [where y =pH = 9 - 10]
so pH value is 5 and 9 respectively

Topic: Chemistry, d and f Block Elements, NEET
Crop improvement is possible through:

Options:
A Judicious combination of evaluation and selection, hybridisation and testing and commercialisation
B Selection and hybridisation only
C Scientific improvement of cultivated plants
D Selection and testing of superior recombinants

The correct answer is:
Judicious combination of evaluation and selection, hybridisation and testing and commercialisation

Solution:
Plant breeders generally select the different plants with desired characters and cross them to obtain desired trait in the offspring. Once they are crossed, the superior recombinants are selected, tested and commercialised.

Topic: Biology, Strategies for Enhancement in Food Production, NEET
Crop plants grown in monoculture are:

Options:
A highly prone to pests
B low in yield
C free from intraspecific competition
D characterised by poor root system

The correct answer is:
highly prone to pests

Solution:
Monoculture involves the exclusive cultivation of a single crop over wide areas. It carries the risk of an entire crop being destroyed with the appearance of a single pest species or disease.

Topic: Biology, Strategies for Enhancement in Food Production, NEET, NEET 2006
Crop plants grown in monoculture are

Options:
A Free from intraspecific competition
B Characterised by poor roots system
C Highly prone to pests
D Low in yield

The correct answer is:
Highly prone to pests

Solution:
Monoculture is the agricultural practice of producing or growing a single crop or plant species over a wide area and for a large number of consecutive years. Monocultures can lead to the quicker spread of pests and diseases, where a uniform crop is susceptible to a pathogen. 'Crop monoculture' is the practice of growing the same crop year after year.

Topic: Biology, Environmental Issues, NEET
Crop rotation with legume or grass pasture to improve soil structure and fertility is called,

Options:
A Ley farming
B Contour farming
C Strip farming
D Shifting agriculture

The correct answer is:
Ley farming

Solution:
Ley agriculture helps to increase the soil fertility and improve the physical texture of the soil. The growth of grass or legumes in rotation with grain or tilled crops is done as a soil conservation measure. The cultivation is done for hay, silage, and pasture to meet maximum livestock needs.

Topic: Biology, Environmental Issues, NEET, NEET 2016 (Phase 1)
Crossing over in diploid organism is responsible for

Options:
A Segregation of alleles
B Dominance of genes
C Linkage between genes
D Recombination of genes

The correct answer is:
Recombination of genes

Solution:
Crossing over involves physical exchange of genetic material between non sister chromatids of homologous chromosomes and leads to recombination.

Topic: Biology, Cell Cycle and Cell Division, NEET
Crossing over occurs between ________chromatid of _______chromosome.

Options:
A Sister, homologous
B Non-sister, homologous
C Non-sister, non homologous
D Sister, homologous

The correct answer is:
Non-sister, homologous

Solution:
Crossing over is the exchange of chromosomal segment between non-sister chromatids of homologous chromosomes. It occurs during pachytene of prophase-I of meiosis, and it results in recombination of genes, producing genetic variation. It is carried out by enzyme recombinase.

Topic: Biology, Cell Cycle and Cell Division, NEET
Crossing over occurs between

Options:
A Two different genomes
B Homologous chromosome
C Sister chromatid
D Non homologous chromosome.

The correct answer is:
Homologous chromosome

Solution:
In prophase I of meiosis, the replicated homologous pair of chromosomes come together in the process called synapsis, and sections of the chromosomes are exchanged. After crossing over, the resultant chromosomes are neither entirely maternal nor entirely paternal but contain genes from both parents. Synapsis and crossing over occur only in meiosis.

Topic: Biology, Principles of Inheritance and Variation, NEET
Crossing over takes place between which chromatids and in which stage of the cell cycle?

Options:
A Non-sister chromatids of non-homologous chromosomes at zygotene stage of prophase I
B Non-sister chromatids of homologous chromosomes at pachytene stage of prophase I
C Non-sister chromatids of homologous chromosomes at zygotene stage of prophase I
D Non-sister chromatids of non-homologous chromosomes at pachytene stage of prophase I

The correct answer is:
Non-sister chromatids of homologous chromosomes at pachytene stage of prophase I

Solution:
Crossing over takes place between non-sister chromatids of homologous chromosomes at pachytene stage of prophase-I. This stage of prophase- $\mathrm{I}$ in meiosis is characterised by the appearance of recombination nodules, the site at which crossing over occurs between non-sister chromatids of the homologous chromosomes.

Topic: Biology, Cell Cycle and Cell Division, NEET, NEET 2019 (Odisha)
Crossing over that results in genetic recombination in higher organisms occurs between:

Options:
A sister chromatids of a bivalent
B non-sister chromatids of a bivalent
C two daughter nuclei
D two different bivalents.

The correct answer is:
non-sister chromatids of a bivalent

Solution:
Crossing over is the exchange of chromosomal segments between non-sister chromatids of homologous chromosomes during the production of gametes. It occurs during pachytene stage. (Ref. to Fig. 28.4)

Topic: Biology, Principles of Inheritance and Variation, NEET, NEET 2004
Cross-pollinating plants

(i) Produce offsprings having variation among themselves.
(ii) Reduces inbreeding depression.
(iii) Results in the production of pure line homozygous offsprings.
(iv) Having bisexual flowers or have monoecious conditions.

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

The correct answer is:
(i) and (ii) are correct

Solution:
Pollination is the process of transfer of pollen grain from anther to stigma of the female reproductive organ. If the transfer is to a different flower of different plant then it is considered to be cross pollination. Cross pollination promotes variation in the plants thus, supporting evolution process. Cross pollination results in formation of heterozygous condition rather than homozygous condition.
If the transfer of pollen grain is in the same flower or neighboring flower of same plant then it is called self pollination. Self pollination helps develop pure line of offsprings and it generally occurs in bisexual flowers.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
Cross-pollination in crop is known as

Options:
A Chasmogamy
B Cleistogamy
C Autogamy
D Allogamy

The correct answer is:
Allogamy

Solution:
When pollen grains of the flower of one plant is transferred to the stigma of a flower on the other plant of same or different species is called cross-pollination. Autogamy, in contrast, is self-fertilization, e.g. fertilization occurring on a flower when the ovum is fertilized with its own pollen (as in self-pollination). Allogamy is advantageous over autogamy with regard to preventing inbreeding depression, which is the reduced biological fitness in a particular population due to inbreeding. Allogamy is more efficient in encouraging the generation of new genotypes than autogamy.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
Crude sodium chloride obtained by crystallisation of brine solution does not contain

Options:
A $\mathrm{MgSO}_4$
B $\mathrm{Na}_2 \mathrm{SO}_4$
C $\mathrm{MgCl}_2$
D $\mathrm{CaSO}_4$

The correct answer is:
$\mathrm{MgSO}_4$

Solution:
Crude sodium chloride obtained by crystallisation of brine solution contains $\mathrm{CaSO}_4$, $\mathrm{Na}_2 \mathrm{SO}_4, \mathrm{CaCl}_2, \mathrm{MgCl}_2$ as impuirities. $\mathrm{CaCl}_2$ and $\mathrm{MgCl}_2$ are deliquescent, i.e. absorb moisture from atmosphere and give wet appearance to the salt. Crude salt is dissolved in water and insoluble impurities are removed by filtration. Hence, $\mathrm{MgSO}_4$ is not present in crude sodium chloride.

Topic: Chemistry, s Block Elements, NEET, NEET 2019 (Odisha)
cry gene, which synthesizes crystal proteins, is isolated from:

Options:
A Bacillus thuriengiensis
B Rhizobium
C Bacillus polymyxa
D Clostridium

The correct answer is:
Bacillus thuriengiensis

Solution:
Bacillus thuringensis is a bacteria having the capacity to produce an insecticidal protein called bt toxin. This toxin is produced in the inactive form by the cry gene found in the bacterial genome. There are a number of them. cryIAc and cryIIAb control the cotton bollworm and cryIAb controls corn borer. These proteins are produced in inactive form so that the bacteria is not affected by it. When this protein comes in contact with the digestive juices of the gut of the insect, it becomes active. The activated protein bind to the surface of epithelial cells of midgut and create pores. These causes swelling and lysis of cells leading to death of the insect.

Topic: Biology, Biotechnology and Its Applications, NEET
cry-gene is associated with

Options:
A Salmonella typhimurium
B Escherichia coli
C Bacillus thuringiensis
D Bacillus subtilis

The correct answer is:
Bacillus thuringiensis

Solution:
The cry gene family, produced during the late exponential phase of growth in Bacillus thuringiensis, is a large, still-growing family of homologous genes, in which each gene encodes a protein with strong specific activity against only one or a few insect species.

Topic: Biology, Biotechnology and Its Applications, NEET
cryIIAb and cryIAb produce toxins that control

Options:
A Cotton bollworms and corn borer, respectively
B Corn borer and cotton bollworms, respectively
C Tobacco budworms and nematodes, respectively
D Nematodes and tobacco budworms, respectively

The correct answer is:
Cotton bollworms and corn borer, respectively

Solution:
Bt toxin is coded by a gene named Cry. There are a number of them, e.g., the proteins encoded by the genes Cry I Ac and Cry II Ab control the cotton bollworms, that of Cry I Ab controls corn borer.

Topic: Biology, Biotechnology and Its Applications, NEET
Cryopreservation technique is used for :

Options:
A Protection of environment
B Protection of Biodiversity hotspots
C Preservation of gametes in viable and fertile condition for a long period
D In-situ conservation

The correct answer is:
Preservation of gametes in viable and fertile condition for a long period

Solution:
Cryopreservation technique is a type of ex-situ conservation in which gametes of threatened species can be preserved in viable and fertile conditions for long period.
Hence the correct answer is option (3).

Topic: Biology, Biodiversity and its Conservation, NEET, NEET 2024 (Re-NEET)
Cryoscopic constant of a liquid is-

Options:
A Decrease in freezing point when 1gram of solute is dissolved per kg of the solvent
B Decrease in the freezing point when 1mole of solute is dissolved per kg of the solvent
C Is the elevation for 1molar solution?
D Is a factor used for calculation of elevation in boiling point?

The correct answer is:
Decrease in the freezing point when 1mole of solute is dissolved per kg of the solvent

Solution:
The cryoscopic constant is molal freezing point depression constant. It is decreasing in the freezing point of the solution when 1 mole of Solute is dissolved in 1 kg of the solvent.

Topic: Chemistry, Solutions, NEET
Cryptogams do not have

Options:
A Xylem vessels and sieve tubes
B Tracheids and sieve tubes
C Vessels, sieve tubes and companion cells
D Tracheids and companion cells

The correct answer is:
Vessels, sieve tubes and companion cells

Solution:
Pteridophytes are the first successful land plants that had vascular tissues. Xylem consists of tracheids only for conduction, and vessels are absent. Phloem consists of sieve cells only; sieve tubes and companion cells are absent.

Topic: Biology, Plant Kingdom, NEET
Crypts of Leiberkuhn are present in

Options:
A Small intestine
B Liver
C Stomach
D Colon

The correct answer is:
Small intestine

Solution:
Crypts of Leiberkuhn or intestinal glands are present in the duodenum and ileum (parts of the small intestine) only. These are formed by the folding of lamina propria and secrete succus entericus, i.e., intestinal juice.

Topic: Biology, Digestion and Absorption, NEET
Crypts of Lieberkuhn is an example of

Options:
A Simple tubular gland
B Coiled tubular gland
C Simple alveolar gland
D Compound alveolar gland

The correct answer is:
Simple tubular gland

Solution:
Crypts of Lieberkuhn are also called as intestinal glands are example od having simple tubular glands that lie between the villi of the small intestine. The glands and intestinal villi are covered by epithelium which contains multiple types of cells: enterocytes (absorbing water and electrolytes), goblet cells (secreting mucus), enteroendocrine cells (secreting hormones), tuft cells and, at the base of the gland, Paneth cells (secreting anti-microbial substances like defensin molecules and lysozyme ) and stem cells.

Topic: Biology, Digestion and Absorption, NEET
Crystal field spliting energy for high spin $d^4$ octahedral complex is:

Options:
A $-1.2 \Delta_0$
B $-0.6 \Delta_0$
C $-0.8 \Delta_0$
D $-1.6 \Delta_0$

The correct answer is:
$-0.6 \Delta_0$

Solution:
$\mathrm{CFSE}=(-0.4 x+0.6 y) \Delta_0$
$x$ is no of $t_{2 \mathrm{~g}}$ orbital while $\mathrm{y}$ is no of $e_g$ orbital
$$
\begin{aligned}
& =(-0.4 \times 3+0.6 \times 1) \Delta_0 \\
& =-0.6 \Delta_0
\end{aligned}
$$

Topic: Chemistry, Coordination Compounds, NEET, NEET 2013 (Karnataka)
Crystal field stabilization energy for high spin $\mathrm{d}^4$ octahedral complex is

Options:
A $-1.8 \Delta_0$
B $-1.6 \Delta_0+P$
C $-1.2 \Delta_{\circ}$
D $-0.6 \Delta_0$

The correct answer is:
$-0.6 \Delta_0$

Solution:
Key Idea:- In case of high spin complex, $\Delta_0$ is small. Thus, the energy required to pair up the fourth electron with the electrons of lower energy d-orbitals would be higher than that required to place the electrons in the higher d-orbital. Thus, pairing does not occur.
For high spin $\mathrm{d}^4$ octahedral complex,
$\therefore$ Crystal field stabilisation energy
$$
\begin{aligned}
& =(-3 \times 0.4+1 \times 0.6) \Delta_{\circ} \\
& =(-1.2+0.6) \Delta_0 \\
& =-0.6 \Delta_0
\end{aligned}
$$

Topic: Chemistry, Coordination Compounds, NEET, NEET 2010 (Screening)
Crystals if Bt toxin produced by some bacteria do not kill the bacteria themselves because

Options:
A bacteria are resistant to the toxin
B toxin is immature
C toxin is inactive
D bacteria encloses toxin in a special sac

The correct answer is:
toxin is inactive

Solution:
Toxins in bacteria are found in an inactive form known as protoxin. This gets converted into an active form when it moves into the body of an insect.

Topic: Biology, Biotechnology and Its Applications, NEET
CsBr crystallises in a body centred cubic lattice. The unit cell length is $436.6 \mathrm{pm}$. Given that the atomic mass of $\mathrm{Cs}=133$ and that of $\mathrm{Br}=80 \mathrm{amu}$ and Avogadro number being $6.02 \times 10^{23} \mathrm{~mol}^{-1}$. the density of $\mathrm{CsBr}$ is:

Options:
A $4.25 \mathrm{~g} / \mathrm{cm}^3$
B $42.5 \mathrm{~g} / \mathrm{cm}^3$
C $0.425 \mathrm{~g} / \mathrm{cm}^3$
D $8.25 \mathrm{~g} / \mathrm{cm}^3$

The correct answer is:
$4.25 \mathrm{~g} / \mathrm{cm}^3$

Solution:
Density of $\mathrm{CsBr}=\frac{\mathrm{Z} \times \mathrm{M}}{a^3 \times \mathrm{N}_0}$
$\mathrm{Z} \rightarrow$ No. of atoms in the bec unit cell $=2$
$\mathrm{M} \rightarrow$ Molar mass of $\mathrm{CaBr}=133+$ $80=213$
$a \rightarrow$ Edge length of unit cell $=436.6$ $\mathrm{pm}=436.6 \times 10^{-10} \mathrm{~cm}$
$\mathrm{N}_0$ is Avogadro number
$\begin{aligned}
& \therefore \text { Density } \\
& =\frac{2 \times 213}{\left(436.6 \times 10^{-10}\right)^3 \times 6.02 \times 10^{23}} \\
& =8.50 \mathrm{~g} / \mathrm{cm}^3
\end{aligned}$
For a unit cell $=\frac{8.50}{2}$
$=4.25 \mathrm{~g} / \mathrm{cm}^3$
Related Theory
When particles are closed packed resulting in either cpp or hcp structure, two types of voids are generated are Tetrahedral voids are holes or voids. (Coordination number of a tetrahedral void is 4.) Octahedral voids (Coordination number of octahedral void is 6.)

Topic: Chemistry, Solid State, NEET, NEET 2006
Cu 2+ aq + X − aq → R.T. CuX↓+ X 2 , 'X' cannot be

Options:
A Cl-(aq)
B I-(aq)
C CN-(aq)
D SCN-(aq)

The correct answer is:
Cl-(aq)

Solution:
Cu2+(aq) has oxidizing property it oxidize I-(aq),CN-(aq),SCN-(aq) into I 2 ,  (CN) 2 ,  (SCN) 2 respectively but does not oxidize Cl-(aq) as it is a weaker reductant.

Topic: Chemistry, d and f Block Elements, NEET
Cu 65 will turn into Cu 66 if it is bombarded with

Options:
A Protons
B Neutrons
C Electrons
D Alpha particles

The correct answer is:
Neutrons

Solution:
When Cu 65 is bombard with a neutron, the neutron is absorbed in Cu 65 and turn into Cu 66 .

Topic: Physics, Nuclear Physics, NEET
Cu ions released from copper-releasing Intra Uterine Devices (IUDs)

Options:
A make uterus unsuitable for implantation
B increase phagocytosis of sperms
C suppress sperm motility
D prevent ovulation

The correct answer is:
suppress sperm motility

Solution:
Cu ions release by copper-releasing intrauterine devices suppresses sperm motility. Intrauterine devices are inserted by doctors in the uterus through the vagina. They are available as the non-medicated IUDs, copper-releasing IUDs, and hormone-releasing IUDs, these IUDs increase phagocytosis of sperms within the uterus and the Cu ions suppress sperm's motility and fertilizing capacity.
So, the correct answer is 'Suppress sperm motility'.

Topic: Biology, Reproductive Health, NEET, NEET 2010 (Screening)
Cu ions released from copper-releasing intra uterine devices (IUDs)

Options:
A makes uterus suitable for implantation.
B increase phagocytosis of sperms.
C prevent ovulation.
D suppress sperm motility.

The correct answer is:
suppress sperm motility.

Solution:
Intrauterine devices (IUDs) are inserted by doctors or expert nurses in the uterus through the vagina. These intrauterine devices are available as the non-medicated IUDs (e.g., Lippes loop), copper releasing IUDs (CuT, Cu7, Multiload 375) and the hormone-releasing IUDs (Progestasert, LNG-20), IUDs increase phagocytosis of sperms within the uterus and the Cu ions released suppress sperm motility and the fertilizing capacity of sperms. The hormone-releasing IUDs, in addition, make the uterus unsuitable for implantation and the cervix hostile to the sperms.

Topic: Biology, Reproductive Health, NEET
Cu normally exists as which of the following crystal structures?

Options:
A Bcc
B Ccp
C Hcp
D Simple cubic

The correct answer is:
Ccp

Solution:
Correct Option is : 2
Ccp

Topic: Chemistry, d and f Block Elements, NEET