datavorous/entrance-exam-dataset huggingface dataset:
Which one of the following is not used for disinfection of drinking water?

Options:
A chlorine
B ozone
C chloramine
D phenyl.

The correct answer is:
phenyl.

Solution:
In a sewage efficient treatment plan, during the tertiary treatment the decreased water is chlorinated with chlorine or perchlorate salts, ozonised or irradiate with UV to kill pathogens. Phenyl is not used for disinfection of drinking water. Phenyl is a strong deodorant and germicide for disinfecting surfaces, like floors and is extensively used for sanitation purpose.
Related Theory
Tertiary treatment is the final cleaning process that improves wastewater quality before it is reused, recycled or discharged to the environment. The treatment removes remaining inorganic compounds, and substances, such as the nitrogen and phosphorus. Bacteria, viruses and parasites, which are harmful to public health, are also removed at this stage. Alum is used to help remove additional phosphorus particles and group the remaining solids together for easy removal in the filters. Chlorine removes microorganisms in treated wastewater including bacteria, viruses and parasites such as Giardia and Cryptosporidium. The chlorinated water slowly winds its way along the discharge tank, giving it time to react. Any remaining chlorine is removed by adding sodium bisulphite just before it's discharged.
$Å$ Caution
$\rightarrow$ Chlorine and chloramine are the major disinfectants used in public water systems.

Topic: Biology, Microbes in Human Welfare, NEET, NEET 2005
Which one of the following is not used to reduce friction

Options:
A Oil
B Ball bearings
C Sand
D Graphite'

The correct answer is:
Sand

Solution:
Sand is used to increase the friction.

Topic: Physics, Laws of Motion, JEE Main
Which one of the following is now being commercially produced by biotechnological procedures?

Options:
A Nicotine
B Morphine
C Quinine
D Insulin

The correct answer is:
Insulin

Solution:
Now-a-days, genetically engineered insulin is being produced at commercial level. The biotechnological procedure involves the synthesis of two DNA sequences corresponding to $A$ and $B$ insulin chains. The two DNA sequences or genes are made to fuse with plasmids and later allowed to form insulin chains.

Topic: Biology, Biotechnology and Its Applications, NEET, NEET 2010 (Mains)
Which one of the following is resistant to enzyme action?

Options:
A Leaf cuticle
B Cork
C Wood fibre
D Pollen exine

The correct answer is:
Pollen exine

Solution:
Pollen exine : It is formed of sporopollenin which is resistant to microbial, physical and chemical decomposition. Due to presence of sporopollenin, pollens can be preserved for longer period of time in fossil form. Sporopollenin is formed after the oxidative polymerisation of carotenoids.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET, NEET 2008 (Mains)
Which one of the following is strongly basic?

Options:
A Dimethyl amine
B Methyl amine
C Ammonia
D Aniline

The correct answer is:
Dimethyl amine

Solution:
Basic strength of amine increase with increases in strength of electron donating group. In dimethyl amine there are two methyl group with $+I$-effect and is most basic.
While, methyl amine has only one methyl group and ammonia has no methyl group.
In aniline due to resonance the lone pair of amines are delocalised and is least basic.
Basic strength order

Topic: Chemistry, Amines, JEE Main
Which one of the following is the Boolean expression for NOR gate?

Options:
A
$Y=\overline{A+B}$

B
$Y=\overline{A \cdot B}$

C
$Y=A \cdot B$

D
$Y=\bar{A}$

The correct answer is:
$Y=\overline{A+B}$

Solution:
NOR gate is the combination of NOT and OR gate. Boolean expression for NOR gate is $Y=\overline{A+B}$

Topic: Physics, Semiconductors, JEE Main, JEE Main 2012 (19 May Online)
Which one of the following is the correct description of a certain part of a normal human skeleton?

Options:
A Parietal bone and the temporal bone of the skull are joined by fibrous joint
B First vertebra is axis, which articulates with the occipital condyles
C The $9^{\text {th }}$ and $10^{\text {th }}$ pairs of ribs are called the floating ribs
D Glenoid cavity is a depression to which the thigh bone articulates

The correct answer is:
Parietal bone and the temporal bone of the skull are joined by fibrous joint

Solution:
Immovable or fixed or fibrous joints are found between the skull bones. No movement occurs at these joints. So, parietal bone and the temporal bone of the skull are joined by fibrous joint.
Invertebrates, the first vertebra is called atlas, while the second vertebra is axis. In humans, first seven pairs of ribs are called true rubs; $8^{\text {th }}, 9^{\text {th }}$ and $10^{\text {th }}$ pairs of ribs are false ribs while $11^{\text {th }}$ and $12^{\text {th }}$ pairs of ribs are called floating ribs.
Glenoid cavity is a socket-shaped cavity in the scapula (shoulder bone) that holds the head of the humerus in a ball and socket joint.

Topic: Biology, Locomotion and Movement, NEET, NEET 2010 (Mains)
Which one of the following is the correct difference between Rod Cells and Cone Cells of our retina?

Options:
A (1)
B (2)
C (3)
D (4)

The correct answer is:
(4)

Solution:
Rod cells are more concentrated towards the periphery. Visual acuity is highest in fovea centralis which contains only cones. Visual pigment in rods cells is rhodopsin, whereas in the cone cells it is iodopsin.

Topic: Biology, Neural Control and Coordination, NEET, NEET 2008 (Mains)
Which one of the following is the correct matching of the site of action on the given substrate, the enzyme acting upon it and the end product?

Options:
A Stomach : Fats $\stackrel{\text { Lipase }}{\longrightarrow}$ micelles
B Duodenum : Triglycerides $\underset{\text { Trpsin }}{\longrightarrow}$ monoglycerides
C Small intestine : Starch $\underset{\sim \text { Amylase }}{\longrightarrow}$ Disaccharide (Maltose)
D Small intestine : Proteins $\stackrel{\text { Pepsin }}{\longrightarrow}$ Amino acids

The correct answer is:
Small intestine : Starch $\underset{\sim \text { Amylase }}{\longrightarrow}$ Disaccharide (Maltose)

Solution:
Amylase digests complex starch (polysaccharide) molecules into smaller, simpler maltose (disaccharide) molecules.

Topic: Biology, Digestion and Absorption, NEET, NEET 2008 (Mains)
Which one of the following is the correct matching of three items and their grouping category?

Options:
A (1)
B (2)
C (3)
D (4)

The correct answer is:
(3)

Solution:
No Solution Available

Topic: Biology, Locomotion and Movement, NEET, NEET 2009 (Mains)
which one of the following is the correct order of acidic strength?
(i) Cl3C-COOH
(ii) Cl2CH-COOH
(iii) ClCH2-COOH
(iv) CH3-COOH

Options:
A iv >iii > ii >i
B i > ii >iii >iv
C i >iii >ii iv
D iv >ii > iii >i

The correct answer is:
i > ii >iii >iv

Solution:
Acidic nature ∝ −I (Electron withdrawing groups)
More the −I group at α 'C' of carboxylic acid greater the acidic strength.

Topic: Chemistry, General Organic Chemistry, JEE Main
Which one of the following is the correct percentage of the two (out of the total of
4) green house gases that contribute to the total global warming?

Options:
A Methane $20 \%, \mathrm{~N}_2 \mathrm{O} 18 \%$
B CFCs 14%, Methane 20%
C $\mathrm{CO}_2 40 \%$, CFSs $30 \%$
D $\mathrm{N}_2 \mathrm{O} 6 \%, \mathrm{CO}_2 86 \%$

The correct answer is:
CFCs 14%, Methane 20%

Solution:
CFC $14 \%$, methane $20 \%$ : For $\mathrm{CO}_2$ it is $60 \%$ and for $\mathrm{N}_2 \mathrm{O}$ it is $6 \%$

Topic: Biology, Environmental Issues, NEET, NEET 2008 (Mains)
Which one of the following is the correct statement?

Options:
A Boric acid is a protonic acid.
B Both Ti3+ and Al3+ ions act as oxidising agent in aqueous solution.
C Hydrogen bonding in H3BO3 gives it a layered structure.
D BOEt3 imparts blue colour to the burner flamer.

The correct answer is:
Hydrogen bonding in H3BO3 gives it a layered structure.

Solution:
(i) It is a weak monobasic acid soluble in water and in aqueous solution boron atom completes its octet by accepting OHâ from water molecules:
BOH3+2H2OâBOH4-+ H3O+
(ii) Only Tl3+ acts as an oxidising agent on account of inert pair effect.
(iii) In the solid state, the BOH3 units are hydrogen bonded together into two dimensional
sheets with almost hexagonal symmetry.
(iv) BOEt3 imparts green colour to the burner flame.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Which one of the following is the correct statement?

Options:
A
Boric acid is a protonic acid

B
Beryllium exhibits coordination number of six

C
Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase

D
$\mathrm{B}_2 \mathrm{H}_6 .2 \mathrm{NH}_3$ is known as 'inorganic benzene'

The correct answer is:
Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase

Solution:

Topic: Chemistry, s Block Elements, JEE Main, JEE Main 2008
Which one of the following is the correct statement regarding the particular psychotropic drug specified?

Options:
A Barbiturates cause relation and temporary euphoria
B Hashish causes after thought perceptions and hallucinations
C Opium stimulates nervous system and causes hallucinations
D Morphine leads to delusions and disturbed emotions

The correct answer is:
Hashish causes after thought perceptions and hallucinations

Solution:
Morphine is both a sedative as well as analgesic drug. Barbiturates are sedatives and have hypnotic effect. Opium is also a narcotic drug which has a depressing effect on CNS.

Topic: Biology, Human Health and Diseases, NEET, NEET 2008 (Mains)
Which one of the following is the correct statement regarding the particular psychotropic drug specified?

Options:
A Morphine leads to delusions and disturbed emotions.
B Barbiturates cause relaxation and temporary euphoria.
C Hashish causes alteration of thoughts, perceptions and hallucinations.
D Opium stimulates nervous system and causes hallucinations.

The correct answer is:
Hashish causes alteration of thoughts, perceptions and hallucinations.

Solution:
Hallucination means apparent perception of external objects or sounds not actually present. It is caused by psychedelic drugs or hallicinogens. The hallucinogens act mainly on CNS (central nervous system) and greatly alter one's thoughts, feelings and perceptions. Hashish is the example of hallucinogen.

Topic: Biology, Human Health and Diseases, AIIMS, AIIMS 2008
Which one of the following is the first popular artificial sweetener?

Options:
A Neotame
B Saccharin
C Sucralose
D Aspartame

The correct answer is:
Saccharin

Solution:
Artificial sweetener is among the most desirable sugar substitutes because it adds few calories to our diet. Saccharin is the oldest non-nutritive sweetener, having been discovered in. Saccharin is around 300 times sweeter than sucrose.

Topic: Chemistry, Chemistry in Everyday Life, JEE Main
Which one of the following is the incorrect matching of the events occurring during the menstrual cycle?

Options:
A The tertiary follicle further changes into the mature follicle or Graafian follicle.
B Development of corpus luteum in the proliferative phase with increased secretion of progesterone.
C The secondary oocyte forms a new membrane called zona pellucida.
D The Graafian follicle ruptures to release the secondary oocyte (ovum) from the ovary by the process called ovulation.

The correct answer is:
Development of corpus luteum in the proliferative phase with increased secretion of progesterone.

Solution:
The corpus luteum is essential for establishing and maintaining pregnancy in females. In the ovary, the corpus luteum secretes estrogen and progesterone, which are steroid hormones responsible for the thickening of the endometrium and its development and maintenance, respectively.

Topic: Biology, Human Reproduction, NEET
Which one of the following is the most abundant protein in the animals?

Options:
A Collagen
B Lectin
C Insulin
D Haemoglobin

The correct answer is:
Collagen

Solution:
Collagen is the most abundant protein in the animal world. This is one of the main components of our connective tissue and are associated with bones, cartilages, tendons, skin etc. It is the substance that holds the body together. Collagen forms a scaffold to provide strength and structure.

RuBisCO is the most abundant protein in the whole of the biosphere. RuBisCO is an enzyme involved in carbon fixation (photosynthesis), a process by which the atmospheric CO2 is converted by plants to energy rich molecules i.e. glucose.

Topic: Biology, Structural Organisation in Animals, NEET, NEET 2020 (Phase 1)
Which one of the following is the most likely reason of not occuring regular menstruation cycle in females ?

Options:
A Fertilization of the ovum
B Maintenance of the hypertrophical endometrial lining
C Maintenance of high concentration of sex-hormones in the blood stream
D Retention of well-developed corpus luteum

The correct answer is:
Fertilization of the ovum

Solution:
If fertilization occurs and foetus is implanted in the endometrium, the trophoblast cells of the developing placenta secrete a hormone human Chorionic Gonadotrophic (hCG). This hormone like LH maintains the corpus luteum and the secretion of progesterone and estradiol by it. These two hormones check the breakdown of the endometrium of the uterus. The absence of menstrual bleeding is the earliest sign of pregnancy.

Topic: Biology, Human Reproduction, NEET, NEET 2009 (Screening)
Which one of the following is the most likely root cause why menstruation is not taking place in regularly cycling human female ?

Options:
A Retention of well-developed corpus luteum
B Fertilization of the ovum
C Maintenance of the hypertrophical endometrial lining
D Maintenance of high concentration of sexhormones in the blood stream

The correct answer is:
Fertilization of the ovum

Solution:
No Solution Available

Topic: Biology, Human Reproduction, NEET, NEET 2009 (Mains)
Which one of the following is the strongest base in aqueous solution?

Options:
A
Trimethylamine

B
Aniline

C
Dimethylamine

D
Methylamine

The correct answer is:
Dimethylamine

Solution:
In aqueous solution basicity order of $1^{\circ}, 2^{\circ}$ and $3^{\circ}$ amine with methyl group is
$2^{\circ}>1^{\circ}>3^{\circ}$
In case of aniline lone pair of nitrogen is involved in resonance, so it is weaker base than aliphatic amines.
Hence, (C) is correct.

Topic: Chemistry, Amines, JEE Main
Which one of the following is the strongest base in aqueous solution?

Options:
A
Trimethylamine

B
Aniline

C
Dimethylamine

D
Methylamine

The correct answer is:
Dimethylamine

Solution:
In aqueous solution basicity order of $1^{\circ}, 2^{\circ}$ and $3^{\circ}$ amine with methyl group is
$2^{\circ}>1^{\circ}>3^{\circ}$
In case of aniline lone pair of nitrogen is involved in resonance, so it is weaker base than aliphatic amines.
Hence, (C) is correct.

Topic: Chemistry, Amines, JEE Main, JEE Main 2007
Which one of the following is the true description about an animal concerned?

Options:
A Earthworm -
The alimentary canal consists of a sequence of pharynx, oesophagus, stomach, gizzard and intestine
B Frog - Body divisible into three regions- head, neck and trunk
C Rat - Left kidney is slightly higher in position than the right one
D Cockroach - 10 pairs of spiracles (2 pairs on thorax and 8 pairs on abdomen)

The correct answer is:
Cockroach - 10 pairs of spiracles (2 pairs on thorax and 8 pairs on abdomen)

Solution:
The respiratory system of cockroach consists of tracheae, tracheoles and spiracles. The main tracheal trunks open to exterior on body surface through 10 pairs of segmentally arranged spiracles. Two pair of spiracles are thoracic (one between pro and mesothorax and other between meso and meta thorax). Eight pairs of spiracle are abdominal (one pair in each of the first eight abdominal segments).
Alimentary canal of earthworm is complete and functionally regioned into buccal chamber, pharynx, oesophagus, gizzard, stomach and intestine.
Frog's body has two main parts, ie, head and trunk. Absence of neck and tail provide convenience in both hopping and swimming.

Topic: Biology, Structural Organisation in Animals, NEET, NEET 2008 (Screening)
Which one of the following is the true description about an animal concerned?

Options:
A Cockroach - 10 pairs of spiracles (2 pairs on thorax and 8 pairs on abdomen)
B Earthworm - The alimentary canal consists of a sequence of pharynx, oesophagus, stomach, gizzard and intestine
C Frog - Body divisible into three regions - head, neck and trunk
D Rat - Left kidney is slightly higher in position than the right one

The correct answer is:
Cockroach - 10 pairs of spiracles (2 pairs on thorax and 8 pairs on abdomen)

Solution:
In rat right kidney is sligtly higher than left because all the organs are concentrated towards left, only in human beings left kidney is higher. In earthworm the correct sequence of alimentary canal is pharynx, oesophagus, gizzard, stomach and intestine. In Frog, neck is absent.

Topic: Biology, Animal Kingdom, NEET, NEET 2008 (Mains)
Which one of the following is the unit vector perpendicular to both \(\vec{a}=-\hat{i}+\hat{j}+\hat{k}\) and \(\overrightarrow{\mathrm{b}}=\hat{\mathrm{i}}-\hat{\mathrm{j}}+\hat{\mathrm{k}}\) ?

Options:
A \(\frac{\hat{\mathrm{i}}+\hat{\mathrm{j}}}{\sqrt{2}}\)
B \(\hat{\mathrm{k}}\)
C \(\frac{\hat{\mathrm{j}}+\hat{\mathrm{k}}}{\sqrt{2}}\)
D \(\frac{\hat{\mathrm{i}}-\hat{\mathrm{j}}}{\sqrt{2}}\)

The correct answer is:
\(\frac{\hat{\mathrm{i}}+\hat{\mathrm{j}}}{\sqrt{2}}\)

Solution:
According to question \(\mathrm{a}=-\hat{i}+\hat{j}+\hat{k}\) and \(\mathrm{b}=\hat{i}-\hat{j}+\hat{k}\)
Then, \(\mathrm{a} \times \mathrm{b}=\left|\begin{array}{lll}\hat{i} & \hat{j} & \hat{k} \\ -1 & 1 & 1 \\ 1 & -1 & 1\end{array}\right|\)
\(\begin{gathered}
=\hat{i}[1+1]-\hat{j}[-1-1]+\hat{k}[1-1]=2(\hat{i}+\hat{j}) \\
\quad \text { and }|\mathrm{a} \times \mathrm{b}|=\sqrt{4+4}=2 \sqrt{2}
\end{gathered}\)
\(\therefore \text { Required unit vector }= \pm \frac{2(\hat{i}+\hat{j})}{2 \sqrt{2}}= \pm \frac{\hat{i}+\hat{j}}{\sqrt{2}}\)

Topic: Mathematics, Vector Algebra, JEE Main
Which one of the following is the weakest kind of bonding in solids

Options:
A Ionic
B Metallic
C Vander Waals
D Covalent

The correct answer is:
Vander Waals

Solution:
Vander Waal force is weak dipole-dipole interaction. Vander Wall's force or bonding is the weakest exists between the two molecules of the solids.

Topic: Physics, Semiconductors, JEE Main
Which one of the following is the wrong assumption of kinetic theory of gases ?

Options:
A
Momentum and energy always remain conserved.

B
Pressure is the result of elastic collision of molecules with the container's wall.

C
Molecules are separated by great distances compared to their sizes.

D
All the molecules move in straight line between collision and with same velocity.

The correct answer is:
All the molecules move in straight line between collision and with same velocity.

Solution:
Molecules move very fast in all directions in a straight line by colliding with each other but with different velocity.

Topic: Chemistry, States of Matter, JEE Main, JEE Main 2013 (25 Apr Online)
Which one of the following is used as Antihistamine?

Options:
A
Omeprazole

B
Chloranphenicol

C
Diphenhydramine

D
Norethindrone

The correct answer is:
Diphenhydramine

Solution:
Diphenhydramine is used as antihistamine.

Topic: Chemistry, Chemistry in Everyday Life, JEE Main, JEE Main 2014 (11 Apr Online)
Which one of the following is used as refrigerant for ice-cream and frozen foods?

Options:
A Dry CO
B Liquid \(\mathrm{CH}_4\)
C Dry ice
D Liquid \(\mathrm{H}_2\)

The correct answer is:
Dry ice

Solution:
The most common use of dry ice is to preserve food, using non-cyclic refrigeration. It is frequently used to pack items that must remain cold or frozen such as ice-cream or biological samples, without use of mechanical cooling.

Topic: Chemistry, Chemistry in Everyday Life, AP EAMCET, AP EAMCET 2019 (22 Apr Shift 1)
Which one of the following is used to make non-stick cookware?

Options:
A poly-ethylene terephthalate
B polyetrafluoroethylene
C PVC
D polystyrene

The correct answer is:
polyetrafluoroethylene

Solution:
Polytetrafluoroethylene or teflon is a tough material, resistance to heat and bad conductor of electricity. It is used for coating the cookware to make them non-sticky.

Topic: Chemistry, Polymers, JEE Main
Which one of the following is used to remove most of plutonium from spent nuclear fuel?

Options:
A BrO3
B I2O5
C ClF3
D O2F2

The correct answer is:
O2F2

Solution:
O2F2 oxidises plutonium to PuF6 and the reaction is used to removing plutonium as PuF6 from spent nuclear fuel.

Topic: Chemistry, d and f Block Elements, JEE Main
Which one of the following is used to remove most of plutonium from spent nuclear fuel?

Options:
A BrO3
B I2O5
C ClF3
D O2F2

The correct answer is:
O2F2

Solution:
O2F2 oxidises plutonium to PuF6 and the reaction is used to removing plutonium as PuF6 from spent nuclear fuel.

Topic: Chemistry, d and f Block Elements, JEE Main, JEE Main 2021 (27 Aug Shift 2)
Which one of the following is wrongly matched?

Options:
A $\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+} \quad-$ Square planar
B $\left[\mathrm{Ni}(\mathrm{CO})_{4}\right] \quad-$ Neutral ligand
C $\left[\mathrm{Fe}\left(\mathrm{CN}_{6}\right)^{3-}\right] \quad-\mathrm{sp}^{3} \mathrm{~d}^{2}$
D $\left[\mathrm{Co}(\mathrm{en})_{3}\right]^{3+} \quad-$ Follows EAN rule

The correct answer is:
$\left[\mathrm{Fe}\left(\mathrm{CN}_{6}\right)^{3-}\right] \quad-\mathrm{sp}^{3} \mathrm{~d}^{2}$

Solution:
(a) In $\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}, \mathrm{Cu}$ is present as $\mathrm{Cu}^{2+}$
$$
\mathrm{Cu}^{2+}=[\mathrm{Ar}] 3 \mathrm{~d}^{9} 4 \mathrm{~s}^{0}
$$
$\left(\mathrm{NH}_{3}\right.$ being a strong field ligand shifts one electron from $3 \mathrm{~d}$ orbital to $4 \mathrm{p}$ orbital.)
(b) $\mathrm{In}\left[\mathrm{Ni}(\mathrm{CO})_{4}\right], \mathrm{CO}$ is a neutral ligand.
(c) $\mathrm{In}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$, Fe is present as $\mathrm{Fe}^{3+}$.
$$
\begin{aligned}
&\mathrm{Fe}^{3+}=[\mathrm{Ar}] 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{0} \\
&{\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}=[\mathrm{Ar}]}
\end{aligned}
$$
Thus, its hybridisation is $\mathrm{d}^{2} \mathrm{sp}^{3}$ not $\mathrm{sp}^{3} \mathrm{~d}^{2}$, ie, it is an inner orbital complex.
(d) $\left[\operatorname{Co}(\mathrm{en})_{3}\right]^{3+}$ contains total 36 electrons, ie, follows EAN rule.

Topic: Chemistry, Coordination Compounds, JEE Main
Which one of the following is/are conjugated dienes?

Options:
A

B

C

D

The correct answer is:

Solution:
Conjugated dienes are those in which alternate single and double bond are present.
hence, $\mathrm{B}$ is the correct option.
Remaining $A, C, D$ are isolated polyenes.

Topic: Chemistry, Hydrocarbons, JEE Main
Which one of the following items gives its correct total number?

Options:
A Cervical vertebrae in humans - 8
B Floating ribs in humans - 4
C Amino acids found in proteins - 16
D Types of diabetes - 3

The correct answer is:
Floating ribs in humans - 4

Solution:
In human beings floatings ribs are 2 pairs (4), i.e. $11^{\text {th }}$ and $12^{\text {th }}$ ribs.

Topic: Biology, Locomotion and Movement, NEET, NEET 2008 (Mains)
Which one of the following lanthanides exhibits +2 oxidation state with diamagnetic nature ? (Given Z for Nd=60,Yb=70,La=57,Ce=58)

Options:
A Nd
B Yb
C Ce
D La

The correct answer is:
Yb

Solution:
La2+Z=57=5 d1
Ce2+Z=58=4f2
Nd2+Z=60=4f4
Yb2+Z=70=4f14
Yb2+ Contain no unpaired electron. So it is diamagnetic and Colourless.

Topic: Chemistry, d and f Block Elements, JEE Main, JEE Main 2021 (31 Aug Shift 1)