datavorous/entrance-exam-dataset huggingface dataset:
Among the elements B, Al, C, and Si, which element has the highest first ionisation enthalpy? Justify your answer.

Options:
A B; because it has a smaller atomic size and stronger electron-electron repulsions.
B Al; because it has a completely filled inner electron shell, reducing its affinity for additional electrons.
C C; because it has a higher nuclear charge, resulting in a stronger attraction for electrons.
D Si; because it has a larger atomic size and tends to lose electrons easily.

The correct answer is:
C; because it has a higher nuclear charge, resulting in a stronger attraction for electrons.

Solution:
Correct Option is : (C)
C; because it has a higher nuclear charge, resulting in a stronger attraction for electrons.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Among the elements B, Al, C, and Si, which element has the most metallic character? Justify your answer.

Options:
A B; because it has the highest number of valence electrons.
B Al; because it has the lowest ionisation energy.
C C; because it has the highest electronegativity.
D Si; because it has a larger atomic size and tends to lose electrons easily.

The correct answer is:
Al; because it has the lowest ionisation energy.

Solution:
Correct Option is : (B)
Al; because it has the lowest ionisation energy.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Among the elements in Group 16, which element has the highest electronegativity value?

Options:
A Oxygen
B Sulphur
C Tellurium
D Polonium

The correct answer is:
Oxygen

Solution:
The paragraph states that next to fluorine, oxygen has the highest electronegativity value among the elements in Group 16.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET
Among the elements with atomic number 9, 12, 16 and 36 which is highly electropositive?

Options:
A Element with atomic number 9
B Element with atomic number 12
C Element with atomic number 16
D Element with atomic number 36

The correct answer is:
Element with atomic number 12

Solution:
Z=9;1s22s22p5
Z=12;1s22s22p63s2
Z=16;1s22s22p63s23p4
Z=36;1s22s22p63s23p63d104s24p6
Here element with atomic number 12 is magnesium and most electropositive here.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Among the elements with atomic number 9, 20, 17 and 36 which is highly electropositive?

Options:
A Element with atomic number 9
B Element with atomic number 36
C Element with atomic number 17
D Element with atomic number 20

The correct answer is:
Element with atomic number 20

Solution:
Z=9;1 s 2 ,2 s 2 ,2 p 5 =F
Z=20;1 s 2 ,2 s 2 ,2 p 6 ,3 s 2 ,3 p 6 ,4 s 2 =Ca
Z=17;1 s 2 ,2 s 2 ,2 p 6 ,3 s 2 ,3 p 5 =Cl
Z=36;1 s 2 ,2 s 2 ,2 p 6 ,3 s 2 ,3 p 6 ,3 d 10 ,4 s 2 ,4 p 6 =Kr
Here element with atomic number 20 is calcium and it is most electropositive here.
F, Cl & Kr are nonmetals & Ca is metal and metals are more electropositive than non-metals.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Among 'The Evil Quartet', which one is considered the most important cause driving extinction of species?

Options:
A Co-extinctions
B Habitat loss and fragmentation
C Over-exploitation for economic gain
D Alien species invasions

The correct answer is:
Habitat loss and fragmentation

Solution:
Loss of biodiversity is one of the major concerns in the modern developmental era. There are four causes, called 'The Evil Quartet', which includes:

Habitat loss and fragmentation. This is the most important cause driving animals and plants to extinction. The most important examples of habitat loss come from tropical rain forests. When large habitats are broken up into small fragments due to various human activities, mammals and birds requiring large territories and certain animals with migratory habits are badly affected, leading to population declines.

Co-extinctions

Over-exploitation for economic gain

Alien species invasions.

Topic: Biology, Biodiversity and its Conservation, NEET, NEET 2023 (All India)
Among the five classes of immunoglobulins in humans, the one that is secretory in nature is

Options:
A Ig A
B Ig E
C Ig M
D Both a and c

The correct answer is:
Both a and c

Solution:
Among the five classes of immunoglobulins in humans, Ig A and Ig M are secretory in nature. This secretory IgA is involved in mucosal defense mechanisms. Compared to IgM, IgA is the most potent secretory antibody.

Topic: Biology, Human Health and Diseases, NEET
Among the following alkaline earth metal halides, one which is covalent and soluble in organic solvents is.

Options:
A Calcium chloride
B Strontium chloride
C Magnesium chloride
D Beryllium chloride

The correct answer is:
Beryllium chloride

Solution:
Due to the high polarising power of Be2+ ion, its compounds are covalent. BeCl2 is readily soluble in organic solvents.

Topic: Chemistry, s Block Elements, NEET, NEET 2021
Among the following characters, which one was not considered by Mendel in his experiments on pea?

Options:
A Stem-Tall or Dwarf
B Trichomes-Glandular or non-glandular
C Seed-Green or Yellow
D Pod-Inflated or Constricted

The correct answer is:
Trichomes-Glandular or non-glandular

Solution:
Mendel had studied 7 pairs of contrasting characters in pea plants in his experiments which are stem height, seed colour, seed shape, pod colour, pod shape, flower position & flower colour.

Nature of trichomes i.e., glandular or non-glandular was not considered by Mendel.

Topic: Biology, Principles of Inheritance and Variation, NEET, NEET 2017
Among the following complexes the one which shows Zero crystal field stabilizations energy (CFSE)

Options:
A NiH2O63+
B FeH2O63+
C CoH2O62+
D CoH2O63+

The correct answer is:
FeH2O63+

Solution:
FeH2O63+
Fe+3=3d5t2g1,1,1eg1,1
So C.F.S.E is =-0.4×3+0.6×2∆0=0

Topic: Chemistry, Coordination Compounds, NEET, NEET 2014
Among the following compounds the one that is most reactive towards electrophilic nitration is

Options:
A benzoic acid
B nitrobenzene
C toluene
D benzene

The correct answer is:
toluene

Solution:
Presence of electron releasing group like $-R,-\mathrm{OH}$ etc., increases the electron density at $o / p$ position and thus, makes the benzene ring more reactive (at $o / p$ positions) towards electrophile. On the other hand, electron withdrawing group like $-\mathrm{COOH},-\mathrm{NO}_2$ etc., if present, reduces electron density and thus, reduces the activity of benzene nucleus towards electrophile. Thus, the order of the given compounds towards electrophilic nitration is
Thus, toluene is most reactive towards electrophilic nitration.

Topic: Chemistry, General Organic Chemistry, NEET, NEET 2012 (Screening)
Among the following compounds, the strongest base is

Options:
A
B
C C6H5–NH2
D CH3–NH–CH3

The correct answer is:

Solution:
Guanidine is the strongest base because its conjugate acid is highly stable due to delocalisation. It has 3 equivalent resona
ating structures.

Topic: Chemistry, General Organic Chemistry, NEET
Among the following edible fishes, which one is a marine fish having a rich source of omega-3 fatty acids?

Options:
A Mystus
B Mangur
C Mrigala
D Mackerel

The correct answer is:
Mackerel

Solution:
Mackerel is a marine fish having rich source of omega-3 fatty acids. These fatty acids are a class of essential polyunsaturated fatty acids with the double bond in the third carbon position from the methyl terminal. They have many powerful health benefits for the body and brain.

Topic: Biology, Strategies for Enhancement in Food Production, NEET, NEET 2016 (Phase 2)
Among the following ethers, which one will produce methyl alcohol on treatment with hot concentrated HI?

Options:
A $\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{O}-\mathrm{CH}_3$
B

C

D

The correct answer is:

Solution:
Given data : It is given to identify among the following ethers which one will produce methyl alcohol on treatment with hot concentrated HI
Explanation
t-Butyl iodide and methyl alcohol are formed when t-Butyl methyl ether reacts with hot concentrated HI acid.
Mechanism

Topic: Chemistry, Alcohols Phenols and Ethers, NEET, NEET 2013 (All India)
Among the following ethers, which one will produce methyl alcohol on treatment with hot concentrated HI?

Options:
A CH3-CH2-CH(CH3)-O-CH3
B (CH3)3C-O-CH3
C (CH3)2CH-CH2-O-CH3
D CH3-CH2-CH2-CH2-O-CH3

The correct answer is:
(CH3)3C-O-CH3

Solution:
In in this reaction a stable tertiary carbocation is possible so SN1 mechanism is used and I- in SN1 is taken with stable carbocation.
In rest other options SN2 mechanism will be used as stable carbocations are not possible hence I- goes with CH3 group to give CH3I and respective alcohols.

Topic: Chemistry, Alcohols Phenols and Ethers, NEET
Among the following groups of plants, the correct set of archegoniate plants is:

Options:
A Bryophyta, pteridophyta, gymnosperms, angiosperms
B Algae, bryophyte, pteridophyte
C Bryophyta, pteridophyta, angiosperm
D Bryophyta, pteridophyta, gymnosperm

The correct answer is:
Bryophyta, pteridophyta, gymnosperm

Solution:
Archegoium is female reproductive part of some plants. Plants having archegonium are called archegoniate. Bryophytes, pteridophytes and bryophytes have archegoium so they are included in archegoniate. This archegonium carries egg cell along with neck cell and neck canal cell.

Topic: Biology, Plant Kingdom, NEET
Among the following, identify the substrate required for the only oxidative reaction that occurs in the process of glycolysis.

Options:
A 3- Phosphoglyceric acid
B Glyceraldehyde 3-phosphate
C Fructose 6-phosphate
D Glucose 6-phosphate

The correct answer is:
Glyceraldehyde 3-phosphate

Solution:
In glycolysis, only one oxidative reaction occurs in which the hydrogen liberated is accepted by NAD+ forming NADH+H+. In this glyceraldehyde 3-phosphate is hydrogen donor and is oxidized to form 1,3 diphosphoglyceric acid.

Topic: Biology, Respiration in Plants, NEET
Among the following ions, which one has the highest paramagnetism?

Options:
A [Cr(H2O)6]3+
B Fe ( H 2 O) 6 2+
C [Cu(H2O)6]2+
D [Zn(H2O)6]2+

The correct answer is:
Fe ( H 2 O) 6 2+

Solution:
Water is a weak-field ligand, so the crystal field splitting paired in lower energy. Hence, electrons are not paired in lower energy d-orbitals (i.e., no pairing of electrons in d-orbitals occurs aganist the Hunds rule).

Species
Oxidation state of central metal ion
Configuration of central metal ion
Number of unpaired d-electrons

A. [Cr(H2O)6]3+
+3
Cr3+(3d3)
3

B. Fe ( H 2 O) 6 2+	+2	Fe2+(3d6)	4

C. [Cu(H2O)6]2+
+2
Cu2+(3d9)
1

D. [Zn(H2O)6]2+
+2
Zn2+(3d10)
0

The more the number of unpaired electrons, the higher is the paramagnetic character of the metal ion, As a result, [Fe(H2O)6]2+ has the highest paramagnetism.

Topic: Chemistry, Coordination Compounds, NEET
Among the following isomeric C4H11N amines, one having the lowest boiling point

Options:
A
B
C
D

The correct answer is:

Solution:
Tertiary amines have low boiling points due to absence of hydrogen bonding among isomeric amines the order is 1 ∘ > 2 ∘ > 3 ∘ .
Boiling point ∝ free of attraction.

Topic: Chemistry, Amines, NEET
Among the following metal carbonyls, the C-O bond order is lowest in

Options:
A [Mn(CO)6]+
B [Fe(CO)5]
C [Cr(CO)6]
D [V(CO)6]-

The correct answer is:
[V(CO)6]-

Solution:
(A) Mn+=3d54s1;in presence of CO, effective configuration=3d64s0.
Three lone pair for back bonding with vacant orbital of C in CO.
(B) Fe0=3d64s2 ;in presence of CO, effective configuration =3d8 .
Four lone pair for back bonding with CO.
(C) Cr0=3d54s1 ;effective configuration =3d6 .
Three lone pair for back bonding with CO.
(D) V-=3d44s2 ;effective configuration =3d6 .
Three lone pair for back bonding with CO.
Maximum back bonding is present in Fe(CO)5 ​therefore, CO bond order is lowest here.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET
Among the following, more than one trophic level in a food chain can be occupied by:

Options:
A Fish and zooplanktons
B Sparrow and insectivorous plants
C Frog and lion
D Grasses and lichens

The correct answer is:
Sparrow and insectivorous plants

Solution:
Limitations of Ecological Pyramid:
i) It does not take into account the same species belonging to two or more trophic levels, e.g., sparrow and insectivorous plants.
ii) It assumes a simple food chain and does not accommodate a food web.
iii) Saprophytes, decomposers, microbes and detritivores are not given any place in ecological pyramids.

Topic: Biology, Ecosystem, NEET
Among the following options, which one could be a monocot root?

Options:
A T.S. of Root with 2 Xylem bundles
B T.S. of Root with 4 Xylem bundles
C T.S. of Root with 8 Xylem Bundles
D T.S. of Root without any Xylem Bundles

The correct answer is:
T.S. of Root with 8 Xylem Bundles

Solution:
As compared to the dicot root which have fewer xylem bundles, there are usually more than six (polyarch) xylem bundles in the monocot root.

Topic: Biology, Anatomy of Flowering Plants, NEET
Among the following outer electronic configurations of atoms, which atom can have the highest oxidation state?

Options:
A (n-1)d3ns2
B (n-1)d5ns1
C (n-1)d8ns2
D (n-1)d5ns2

The correct answer is:
(n-1)d5ns2

Solution:
(n-1)d5ns2 can achieve the maximum oxidation state of + 7.

Topic: Chemistry, Structure of Atom, NEET
Among the following pairs of microbes, which pair has both the microbes that can be used as biofertilisers?

Options:
A Aspergillus and Rhizopus
B Rhizobium and Rhizopus
C Cyanobacteria and Rhizobium
D Aspergillus and Cyanobacteria

The correct answer is:
Cyanobacteria and Rhizobium

Solution:
Biofertilisers are organisms that enrich the nutrient quality of the soil. For example, Cyanobacteria and Rhizobium. Aspergillus and Rhizopus are not used as biofertilisers.

Topic: Biology, Microbes in Human Welfare, NEET, NEET 2019 (Odisha)
Among the following pairs of orbitals which orbital will experience the larger effective nuclear charge: (i) 2s and 3s, (ii) 4d and 4f, (iii) 3d and 3p ?

Options:
A (i) 2s , (ii) 4d and (iii) 3d
B (i) 2s , (ii) 4d and (iii) 3p
C (i) 3s , (ii) 4f and (iii) 3p
D (i) 3s , (ii) 4f and (iii) 3d

The correct answer is:
(i) 2s , (ii) 4d and (iii) 3p

Solution:
Correct Option is : (B)
(i) 2s , (ii) 4d and (iii) 3p

Topic: Chemistry, Structure of Atom, NEET
Among the following quantities, the quantity whose dimension is independent of mass and length is

Options:
A Energy
B Thrust
C Momentum
D Angular velocity

The correct answer is:
Angular velocity

Solution:
[Energy] =ML2T-2
[Thrust] =MLT-2
[Momentum] =MLT-1
[Angular velocity] =M0L0T-1
From the above it is clear that the dimensions of angular velocity is independent of mass and length.

Topic: Physics, Units and Dimensions, NEET
Among the following series of transition metal ions, the one where all metal ions have $3 d^2$ electronic configuration is:
[At. no.s $\mathrm{Ti}=22, \mathrm{~V}=23, \mathrm{Cr}=24, \mathrm{Mn}=$ 25]

Options:
A $\mathrm{Ti}^{3+}, \mathrm{V}^{2+}, \mathrm{Cr}^{3+}, \mathrm{Mn}^{4+}$
B $\mathrm{Ti}^{+}, \mathrm{V}^{4+}, \mathrm{Cr}^{6+}, \mathrm{Mn}^{7+}$
C $\mathrm{Ti}^{4+}, \mathrm{V}^{3+}, \mathrm{Cr}^{2+}, \mathrm{Mn}^{3+}$
D $\mathrm{Ti}^{2+}, \mathrm{V}^{3+}, \mathrm{Cr}^{4+}, \mathrm{Mn}^{5+}$

The correct answer is:
$\mathrm{Ti}^{2+}, \mathrm{V}^{3+}, \mathrm{Cr}^{4+}, \mathrm{Mn}^{5+}$

Solution:
$$
\begin{aligned}
\mathrm{Ti}_{22} & =3 d^2 4 s^2 ; & \mathrm{Ti}^{2+} & =3 d^2 \\
\mathrm{~V}_{23} & =3 d^3 4 s^2 ; & \mathrm{V}^{3+} & =3 d^2 \\
\mathrm{Cr}_{24} & =3 d^4 4 s^2 ; & \mathrm{Cr}^{4+} & =3 d^2 \\
\mathrm{Mn}_{25} & =3 d^5 4 s^2 ; & \mathrm{Mn}^{5+} & =3 d^2
\end{aligned}
$$
Related Theory
$\mathrm{Mn}^{2+}$ has the maximum number of unpaired electrons (5) and hence has the maximum magnetic moment.

Topic: Chemistry, d and f Block Elements, NEET, NEET 2004
Among the following sets of bases, which set of bases is present both in DNA and RNA ?

Options:
A Adenine, uracil, thymine
B Adenine, guanine, cytosine
C Adenine, guanine, uracil
D Adenine, guanine, thymine

The correct answer is:
Adenine, guanine, cytosine

Solution:
Adenine, guanine, cytosine sets of bases is present both in DNA and RNA.

Topic: Chemistry, Biomolecules, NEET
Among the following sets of reactants which one produces Anisole?

Options:
A C6H5–CH3;CH3COCl;AlCl3
B C6H5OH;NaOH;CH3I
C CH3CHO;RMgX
D C6H5OH;neutral FeCl3

The correct answer is:
C6H5OH;NaOH;CH3I

Solution:
Phenol reacts with NaOH followed by reaction with methyl iodide to give Anisole as follows.

Topic: Chemistry, Alcohols Phenols and Ethers, NEET
Among the following sets of reactions, which one produces anisole?

Options:
A CH3CHO;RMgX
B C6H5OH;NaOH;CH3I
C C6H5OH; neutral FeCl3
D C6H5-CH3;CH3COCl;AlCl3

The correct answer is:
C6H5OH;NaOH;CH3I

Solution:
1
(2)
(Williamson's synthesis)
(3) C6H5OH+ neutral FeCl3→ Violet colour complex
4 C6H5-CH3+CH3COCl+AlCl3→ Para-methyl acetophenone.

Topic: Chemistry, Alcohols Phenols and Ethers, NEET, NEET 2014
Among the following solids, Schottky defect is NOT observed in-

Options:
A ZnS
B NaCl
C KCl
D CsCl

The correct answer is:
ZnS

Solution:
ZnS shows Frenkel defect due to the smaller ion (usually the cation) is dislocated does not chow Schottky defect.

.

Topic: Chemistry, Solid State, NEET
Among the following statements, incorrect statement is

Options:
A The oceanic reservoir regulates the amount of carbon dioxide in the atmosphere
B It is estimated that 4 × 1010 kg of carbon is fixed in the biosphere through photosynthesis annually.
C Of the total quantity of global carbon, 71% carbon is found dissolved in ocean.
D Carbon constitutes 49% of the dry weight of organisms and is next to the water.

The correct answer is:
It is estimated that 4 × 1010 kg of carbon is fixed in the biosphere through photosynthesis annually.

Solution:
Carbon cycling takes place through atmosphere, ocean and through living and dead organisms. Fossil fuel also represents a reservoir of carbon. During photosynthesis comparatively large amount of carbon is fixed annually in the biosphere. And again a considerable amount of carbon is returned back to the atmosphere as CO2 through the respiration of different flora and fauna. Decomposers also contribute substantially to the CO2 pool by their processing of waste materials and dead organic matter of land or oceans. It is estimated that 4 Ã 1013 kg of carbon is fixed in the biosphere through photosynthesis annually.

Topic: Biology, Ecosystem, NEET
Among the following statements, which is true about boron compounds?

Options:
A BF3⇒ least acidic among the boron halides
B BF3⇒ does not hydrolyses
C B2H6⇒does not have banana bond
D All are incorrect

The correct answer is:
BF3⇒ least acidic among the boron halides

Solution:
BF3 is least acidic among boron halide.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Among the following substituted silanes the one which will give rise to cross linked silicone polymer on hydrolysis is

Options:
A R3SiCl
B R4Si
C RSiCl3
D R2SiCl2

The correct answer is:
RSiCl3

Solution:
It is trichloro alkyl silane which hydrolysed to RSi(OH)3 . This can form three Si-O-Si linkages, thus produces cross linked polymers.

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Among the following the achiral amino acid is

Options:
A Ethylalanine
B Methylglycine
C 2-Hydroxymethylserine
D Tryptophan

The correct answer is:
2-Hydroxymethylserine

Solution:
Among the following the achiral amino acid is 2-Hydroxymethylserine as it does not contain a chiral centre.
HOH2C-C||-COOHNH2 CH2OH

Topic: Chemistry, Biomolecules, NEET
Among the following the coloured compound is

Options:
A Cu 2 Cl 2
B K3[CuCN4]
C CuF2
D CuCH3CN4BF4

The correct answer is:
CuF2

Solution:
In CuF2, Cu2+ ion exist, having d9 configuration. Unpaired electron causes colour (d-d transition). In the crystalline form, CuF2 is blue coloured.
While in other compounds Cu is in positive one oxidation state and does not have unpaired electron. Hence all are colourless.

Topic: Chemistry, d and f Block Elements, NEET
Among the following, the compound that is both paramagnetic and coloured is -

Options:
A K2Cr2O7
B KMnO4
C CoSO4
D K3CuCN4

The correct answer is:
CoSO4

Solution:
CoSO4 have d7 configuration because Co2+=3d7 4sÂ°, thus it both paramagnetic as well as coloured.\
K 2 Cr 2 O 7 and KMnO 4 are colured due in change spectra.

Topic: Chemistry, d and f Block Elements, NEET
Among the following, the correct options for pre-fertilization events are:

a. Gametogenesis
b. Gametes transfer
c. Growth of pollen tube
d. Syngamy
e. Embryogenesis

Options:
A c, d & e
B a, b & c
C b, c & d
D a, b & d

The correct answer is:
a, b & c

Solution:
Syngamy or fertilisation is the fusion of male gamete with female gamete which results in the formation of zygote. This zygote undergoes mitosis, and this results in the formation of embryo by a process called embryogenesis. Thus, syngamy and embryogenesis are post-fertilization events.

Topic: Biology, Reproduction in Organisms, NEET
Among the following, the correct order of acidity is:

Options:
A HClO3<HClO4<HClO2<HClO
B HClO<HClO2<HClO3<HClO4
C HClO2<HClO<HClO3<HClO4
D HClO4<HClO2<HClO<HClO3

The correct answer is:
HClO<HClO2<HClO3<HClO4

Solution:
Acidic strength ∝ stability of conjugate base (Anion)
stability of conjugate base ∝ less charge density ∝ more charge delocalisation ∝ resonating structure
Oxidation state of chlorine ∝ Acidity of Oxo Acid.
HClO<HClO2<HClO3<HClO4 is the correct increasing order.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), NEET, NEET 2016 (Phase 1)
Among the following, the equation which represents a progressive wave is

Options:
A y=Acosaxsinbt
B y=Asinbt
C y=Acos(ax+bt)
D y=Atan(ax+bt)

The correct answer is:
y=Acos(ax+bt)

Solution:
If after t time, displacement of particle is y, then the rquation of progressive wave
Y=Acos(ax+bt)

Topic: Physics, Waves and Sound, NEET
Among the following, the essential amino acid is:

Options:
A Valine
B Alanine
C Serine
D Aspartic acid

The correct answer is:
Valine

Solution:
Valine is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group, an α-carboxylic acid group, and a side chain isopropyl group, making it a non-polar aliphatic amino acid

Topic: Chemistry, Biomolecules, NEET
Among the following, the formula of saturated fatty acid is

Options:
A C17H29COOH
B C17H35COOH
C C17H31COOH
D C17H33COOH

The correct answer is:
C17H35COOH

Solution:
The general formula for saturated fatty acid is CnH2n+1COOH .
Among the given acids, only C17H35COOH satisfy this formula, hence it is a saturated fatty acid.

Topic: Chemistry, Carboxylic Acid Derivatives, NEET
Among the following, the least stable resonating structure is

Options:
A
B
C
D

The correct answer is:

Solution:
As same charges are present at nearest position so structure in option A is least stable. Here structure in option B is most stable one as charges are properly placed at opposite charges are closer too.

Topic: Chemistry, General Organic Chemistry, NEET
Among the following the pair in which the two species are not isostructural is:

Options:
A $\mathrm{SiF}_4$ and $\mathrm{SF}_4$
B $\mathrm{IO}_3^{-}$and $\mathrm{XeO}_3$
C $\mathrm{BH}_4^{-}$and $\mathrm{NH}_4^{+}$
D $\mathrm{PF}_6^{-}$and $\mathrm{SF}_6$

The correct answer is:
$\mathrm{SiF}_4$ and $\mathrm{SF}_4$

Solution:
$\mathrm{SiF}_4$ and $\mathrm{SF}_4$ are not isostructural because $\mathrm{SiF}_4$ is tetrahedral due to $s p^3$ hybridisation while $\mathrm{SF}_4$ has distorted tetrahedral geometry due to presence of lone pair.
Related Theory
Two molecules are isostructural if they have a similar number of atoms arranged in a similar structure (spatial coordinates).
Caution
If they have same number of lone pair and bond pair, they are considered as isostructural.

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET, NEET 2004