datavorous/entrance-exam-dataset huggingface dataset:
Which part of the alimentary canal of cockroach has an outer layer of thick circular muscles and inner cuticle forming six highly chitinous plates called teeth?

Options:
A Gizzard
B Crop
C Proventriculus
D Both a and c

The correct answer is:
Both a and c

Solution:
The alimentary canal in cockroaches is divided into three parts: foregut, midgut, and hindgut. Foregut consists of mouth, esophagus, crop, and gizzard. The crop is the largest part of the foregut. Its main function is to store food. The gizzard is also known as proventriculus. Food from crop enters the gizzard. The gizzard is made up of muscles and also consists of teeth in the inner layer and thus it helps in grinding. Food from the gizzard then enters the midgut where remaining grinding and absorption takes place.

Topic: Biology, Structural Organisation in Animals, NEET
Which part of the brain is responsible for thermoregulation?

Options:
A Cerebrum
B Hypothalamus
C Corpus callosum
D Medulla oblongata

The correct answer is:
Hypothalamus

Solution:
The hypothalamus is a section of the brain that controls thermoregulation. Thermoregulation is a biological process that helps the body to maintain its core internal temperature, which in turn helps in the maintenance of the homeostasis, a state of equilibrium. Healthy internal body temperature falls within a narrow window and if it's hampered, the body will fall sick. Hence, thermoregulation is absolutely necessary.

Topic: Biology, Neural Control and Coordination, NEET, NEET 2019 (All India)
Which part of the human ear plays no role in hearing as such but is otherwise very much required?

Options:
A Eustachian tube
B Organ of Corti
C Vestibular apparatus
D Ear ossicles

The correct answer is:
Vestibular apparatus

Solution:
The inner ear contains a complex system called vestibular apparatus, located above the cochlea. It has no role in hearing but is influenced by gravity and movements. Its specific receptors called crista and macula are responsible for maintenance of balance of the body and posture.

Topic: Biology, Neural Control and Coordination, NEET, NEET 2012 (Screening)
Which part of the mammalian brain controls muscular co-ordination?

Options:
A Cerebrum
B Medulla oblongata
C Cerebellum
D Corpus callosum

The correct answer is:
Cerebellum

Solution:
Cerebellum primary functions is to maintain posture, orientation and equilibrium of body by co-ordinating and regulating tone and contraction of voluntary muscles, mainly according to the commands of cerebellum.

Topic: Biology, Neural Control and Coordination, NEET
Which part of the protein molecule is responsible for function and activity of the proteins

Options:
A Secondary structure
B Peptide bond
C Primary structure
D Binding sites

The correct answer is:
Peptide bond

Solution:
Peptide bond responsible for function and activity of the proteins tas it link amino acid residues in a polypeptide are formed in a condensation reaction between the acidic carboxyl group of one amino acid and the basic amino group of another amino acid.

Topic: Chemistry, Biomolecules, JEE Main
Which part of the world has a high density of organism?

Options:
A Deciduous forests
B Grasslands
C Tropical rain forests
D Savannahs

The correct answer is:
Tropical rain forests

Solution:
Tropical rain forests are mainly found in central America, along Amazon and Orinoco rivers, South America, Congo river basin of Africa, Malagasy Republic and South east Asia including India. Diversity of life is so high that a hectare of the forest may have as many as 200 species of trees, \(70 \%-80 \%\) of all insects and \(80-85 \%\) of all birds are known from tropical forests. Productivity of this biome is also very high and life is abundant. It has different varieties and number of plants and animals.

Topic: Biology, Biodiversity and its Conservation, AIIMS, AIIMS 2007
Which part/s is likely to be affected in the ear when an individual feels giddiness, loses body balance and suffers from ear disease?

Options:
A Organ of corti
B Tectorial membrane and Reissner's membrane
C Crista ampullaris and macula
D Eustachian tube

The correct answer is:
Crista ampullaris and macula

Solution:
The crista and macula are the specific receptors of the vestibular apparatus responsible for the maintenance of the balance of the body and posture. Crista ampullaris is present in the semi-circular ducts. It is responsible for dynamic equilibrium. The macula of the utricle and macula of the sacculus is present in the vestibule. They are responsible for static equilibrium

Topic: Biology, Neural Control and Coordination, NEET
Which parts of a cell contain ribosomes?

I. Chloroplast
II. Mitochondrion
III. Nucleus
IV. Cytoplasm

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

The correct answer is:
I, II, III and IV

Solution:
Ribosome is a structure found in the cell whose main function is protein synthesis. Ribosome is found attached to RER or scattered in cytoplasm as free ribosomes. Nucleus has ribosome and ribosome is synthesised in nucleus. Mitochondria and chloroplast are organelles which have their own DNA and ribosome.

Topic: Biology, Cell - The Unit of Life, NEET
Which physical property of di-hydrogen is wrong?

Options:
A Tasteless gas
B Odourless gas
C Colourless gas
D Non-inflammable gas

The correct answer is:
Non-inflammable gas

Solution:
H2 Is the lightest element ever and is a tasteless, odourless, colourless, and highly combustible gas. It's also in most organic compounds

Hydrogen is a highly inflammable gas. This is because it burns in air to give water.

The reaction is as follows:

2H2​+O2​→2H2​O.

Topic: Chemistry, Hydrogen, JEE Main, JEE Main 2015 (11 Apr Online)
Which pigment acts directly to convert light energy to chemical energy?

Options:
A
Chlorophyll- $a$

B
Chlorophyll- $b$

C
Xanthophyll

D
Carotenoid

The correct answer is:
Chlorophyll- $a$

Solution:
Chlorophyll- $a$ directly acts to convert light energy to chemical energy.
The other pigments chlorophyll- $b$, xanthophyll and carotenoids are accessory pigments associated with the main pigment, i.e., chlorophyll- $a$ harvest the light energy.

Topic: Biology, Photosynthesis in Higher Plants
Which polymer can be used for making contact lenses for eyes

Options:
A Polymethylmethacrylate
B Polyethelene
C Polyethylacrylate
D Nylon-6

The correct answer is:
Polymethylmethacrylate

Solution:
Also known as PMMA. It is a transparent, excellent light transmitter and its optical clarity better than glass so it is used in the preparation of lenses for eyes.

Topic: Chemistry, Polymers, JEE Main
Which polymer has 'chiral' monomer(s)?

Options:
A Neoprene
B Buna -N
C Nylon 6,6
D PHBV

The correct answer is:
PHBV

Solution:
Polymers	Monomers

1) Buna–N	CH2=CH-CH=CH2 & CN-CH=CH2

2) Neoprene- CH2-CH=CCI-CH2n-

3) NYLON -6,6: ~COCH26NHN~	HO2C-CH24-CO2H&H2N-CH26-NH2

4)

In PHBV, both monomers have chiral centre.
3-Hydroxbutanoicacid3-Hydroxypertanoicacid

Topic: Chemistry, Polymers, JEE Main, JEE Main 2020 (09 Jan Shift 2)
Which polymer is used in the manufacture of paints and lacquers?

Options:
A Poly vinyl chloride
B Bakelite
C Glyptal
D Polypropene

The correct answer is:
Glyptal

Solution:
Glyptal is polymer of glycerol and phthalic anhydride.

Topic: Chemistry, Polymers, JEE Main, JEE Main 2015 (04 Apr)
Which position for hydrogen explain all its properties

Options:
A At the top of halogen
B At the top of alkali metals
C At the top of carbon family
D None of these

The correct answer is:
None of these

Solution:
Hydrogen is unique because it has properties of more than one group of elements

Topic: Chemistry, Hydrogen, JEE Main
Which primitive unit cell has unequal edge lengths a≠b≠c and all axial angles different from 90o

Options:
A Hexagonal
B Monoclinic
C Triclinic
D Tetragonal

The correct answer is:
Triclinic

Solution:
The most inorganized system has a≠b≠c and α≠β≠γ=90o is called the triclinic system.

Topic: Chemistry, Solid State, JEE Main, JEE Main 2019 (10 Jan Shift 1)
Which product will be obtained by Grignard reaction, when Formaldehyde reacts with Ethyl magnesium iodide?

Options:
A 2 - Propanol
B 1 - Propanol
C Ethanol
D 2 - Methyl, 2 - Propanol

The correct answer is:
1 - Propanol

Solution:
HCHO + C 2 H 5 Mg I → C 2 H 5 - C | H | OH - H (1 - propanol)
C2H5-CH2-OH is formed in the reaction.

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Which property of $\mathrm{CO}_2$ makes it biologically and geo-chemically important ?

Options:
A Its colourless and odourless nature
B Its low solubility in water
C Its high compressibility
D Its acidic nature

The correct answer is:
Its low solubility in water

Solution:
The property of low solubility of carbon dioxide in water makes it biologically and geo-chemically important. Carbon dioxide on reaction with water form carbonic acid, which dissociates to give $\mathrm{HCO}_3^{-}$ions. $\mathrm{H}_2 \mathrm{CO}_3 / \mathrm{HCO}_3^{-}$ buffer system helps to maintain pH of blood between $7.26-7.42$.

Topic: Chemistry, p Block Elements (Group 13 & 14), KCET, KCET 2022
Which quantum number is not related with Schrodinger equation

Options:
A Principal
B Azimuthal
C Magnetic
D Spin

The correct answer is:
Spin

Solution:
Spin quantum number does not related with Schrodinger equation because they always show $+1 / 2,-1 / 2$ value.

Topic: Chemistry, Structure of Atom, JEE Main
Which radicals are precipitated in $\left(\mathrm{NH}_4\right)_2 \mathrm{CO}_3$ in presence of alkali

Options:
A $\mathrm{Ca}, \mathrm{Ba}, \mathrm{Sr}$
B $M g$
C Both
D None

The correct answer is:
$\mathrm{Ca}, \mathrm{Ba}, \mathrm{Sr}$

Solution:
$\mathrm{Ca}, \mathrm{Ba}, \mathrm{Sr}$ these radicals are precipitated in basic medium

Topic: Chemistry, Practical Chemistry, JEE Main
Which reactant will give the following alcohol on reaction with one mole of phenyl magnesium bromide PhMgBr followed by acidic hydrolysis?

Options:
A CH3–C≡N
B Ph-C≡N
C

D

The correct answer is:

Solution:
Phenyl magnesium bromide is called Grignard reagent. One mole of this react with carbonyl compound to give alcohols. It react with aldehyde to form secondary alcohol while with ketones gives tertiary alcohols. The given compound is a tertiary alcohol so, reactant should be a ketone.

Topic: Chemistry, Aldehydes and Ketones, JEE Main, JEE Main 2022 (26 Jul Shift 1)
Which reaction coordinate diagram best describe the energetics of the following nucleophilic acyl substitution reaction?\(\mathrm{RCOCl}(1)+\mathrm{NH}_{3}(2) \longrightarrow \mathrm{RCONH}_{2}(3)+\mathrm{HCl}(4)\)

Options:
A
Reaction coordinate
B
C
Reaction coordinate
D
Reaction coordinate

The correct answer is:
Reaction coordinate

Solution:
A more reactive (less stable) acid derivative is being converted into more stable acid derivative.
Amide is highly stable compound and will have less energy. On the reactants side acid chloride is very reactive i,e. unstable i,e. High energy.
It is a two step reaction

Topic: Chemistry, Amines, JEE Main
Which reaction does not occur in roasting process.

Options:
A HgS+2HgO→Δ3Hg+SO2
B PbS+2PbO→Δ3Pb+SO2
C ZnS+2ZnO→Δ3Zn+SO2
D None of these

The correct answer is:
ZnS+2ZnO→Δ3Zn+SO2

Solution:
On roasting HgS and PbS sulphides ores are partly converted into their respective oxides. Since the oxides of Hg and Pb are unstable. While that of zinc is stable, therefore, oxides of Hg and Pb bring about the reduction of their sulphides to metals, but zinc oxides does not reduce ZnS to Zn metal

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main
Which reaction, intermediate is formed during the condensation reaction between acetaldehyde and formaldehyde ?

Options:
A $: \overline{\mathrm{CH}}_{2} \mathrm{CHO}$
B $\mathrm{C}_{2}^{+} \mathrm{CHO}$
C $\stackrel{+}{\mathrm{CH}_{2} \mathrm{OH}}$
D $: \overline{\mathrm{C}} \mathrm{HCHO}$

The correct answer is:
$: \overline{\mathrm{CH}}_{2} \mathrm{CHO}$

Solution:
The $\alpha$ -hydrogen atoms of acetaldehyde due to $-E$ effect of $>\mathrm{C}=\mathrm{O}$ group is slightly acidic
in nature. In crossed aldol condensation between formaldehyde and acetaldehdye in the first step $\mathrm{OH}^{-}$ ion (from the base added) abstracts one of these acidic $\alpha$ -hydrogens to form carbanion or enolate ion which is stabilised by resonance.

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Which reaction produce 1-methylcyclohexene

Options:
A
B
C
D

The correct answer is:

Solution:
In A product is
In B product is
In C product is
In D product is

Topic: Chemistry, Hydrocarbons, JEE Main
Which reagent can be used to convert a carboxylic acid chloride into a ketone?

Options:
A Chromic acid
B PCP
C Diborane, hydrogen peroxide
D An organolithium compound

The correct answer is:
An organolithium compound

Solution:
Carboxylic acid chloride were converted directly in good yields into ketones using excess alkyl lithiumcuprates (R 2 CuLi) .

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which reagent can be used to convert an alkene into a glycol?

Options:
A $\mathrm{Br}_2 / \mathrm{CCl}_4$
B $\mathrm{H}_2 \mathrm{SO}_4$
C $\mathrm{OsO}_4$ followed by $\mathrm{NaHSO}_3$
D $\mathrm{HCl}$

The correct answer is:
$\mathrm{OsO}_4$ followed by $\mathrm{NaHSO}_3$

Solution:
$\mathrm{OsO}_4$ followed by $\mathrm{NaHSO}_3$
Explanation: Osmium tetroxide $\left(\mathrm{OsO}_4\right)$ followed by sodium bisulfite $\left(\mathrm{NaHSO}_3\right)$ is used to dihydroxylate alkenes, converting them into glycols (vicinal diols).

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which reagent can be used to reduce a ketone to a secondary alcohol?

Options:
A $\mathrm{H}_2 / \mathrm{Pd}$
B PCC (Pyridinium chlorochromate)
C $\mathrm{NaBH}_4$
D $\mathrm{KMnO}_4$

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

Solution:
$\mathrm{NaBH}_4$
Explanation: Sodium borohydride $\left(\mathrm{NaBH}_4\right)$ is a mild reducing agent that reduces ketones to secondary alcohols

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which reagent can convert a nitrile to an amide?

Options:
A $\mathrm{LiAlH}_4$
B $\mathrm{H}_2 \mathrm{O} / \mathrm{H}^{+}$
C $\mathrm{SOCl}_2$
D $\mathrm{NaOH}$

The correct answer is:
$\mathrm{SOCl}_2$

Solution:
$\mathrm{H}_2 \mathrm{O} / \mathrm{H}^{+}$
Explanation: Nitriles can be hydrolyzed to primary amides using acidic or basic conditions. Water in the presence of an acid $\left(\mathrm{H}^{+}\right)$ facilitates this conversion.

Topic: Chemistry, Amines, JEE Main
Which reagent can convert acetic acid into ethanol?

Options:
A Na + alcohol
B LiAlH4 + ether
C H2+Pt
D Sn+HCl

The correct answer is:
LiAlH4 + ether

Solution:
LiAlH4+ ether, is reducing agent.
It reduce all types of carboxylic acids to alcohols. So, this reagent can be use to convert acetic acid into ethanol. CH 3 COOH â LiAlH 4 /ether CH 3 CH 2 OH

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which reagent is used in the Rosenmund reduction to prepare aldehydes from acyl chlorides?

Options:
A $\mathrm{H}_2 / \mathrm{Pd}$
B $\mathrm{H}_2 / \mathrm{Pd}-\mathrm{BaSO}_4$
C $\mathrm{NaBH}_4$
D $\mathrm{LiAlH}_4$

The correct answer is:
$\mathrm{H}_2 / \mathrm{Pd}-\mathrm{BaSO}_4$

Solution:
$\mathrm{H}_2 / \mathrm{Pd}-\mathrm{BaSO}_4$
Explanation: Rosenmund reduction involves the hydrogenation of acyl chlorides to aldehydes using palladium on barium sulfate as a catalyst, often poisoned with sulfur or quinoline to prevent over-reduction to alcohols.

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which reagent will bring about the conversion of carboxylic acids into esters

Options:
A $\mathrm{C}_2 \mathrm{H}_3 \mathrm{OH}$
B Dry $\mathrm{HCl}+\mathrm{C}_2 \mathrm{H}_3 \mathrm{OH}$
C $\mathrm{LiAlH}_4$
D $\mathrm{Al}\left(\mathrm{OC}_2 \mathrm{H}_3\right)_3$

The correct answer is:
Dry $\mathrm{HCl}+\mathrm{C}_2 \mathrm{H}_3 \mathrm{OH}$

Solution:

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which refining process is generally used in the purification of low melting metals?

Options:
A Chromatographic method
B Electrolysis
C Zone refining
D Liquation

The correct answer is:
Liquation

Solution:
Liquification of liquation: In this method a low melting metal like tin can be made to flow on a sloping surface. In this way it is separated from higher melting impurities.

This process is used for the purification of the metal in which melting point of the metal to be purified should be lower than that of each of the impurities associated with the metal. This process is used for the purification of Sn and Zn, and for removing Pb from Zn-Ag alloy.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main, JEE Main 2021 (27 Aug Shift 1)
Which region of the atmosphere is the
domain of all living organisms

Options:
A Troposphere
B Stratosphere
C Mesosphere
D Thermosphere

The correct answer is:
Troposphere

Solution:
The troposphere is the lowest portion of Earth's atmosphere and is also where all weather takes place. It contains approximately $75 \%$ of atmospheric mass and $99 \%$ of its water vapour and aerosols.

Topic: Chemistry, Environmental Chemistry, AP EAMCET, AP EAMCET 2021 (24 Aug Shift 1)
Which represents an alkane

Options:
A $\mathrm{C}_5 \mathrm{H}_8$
B $\mathrm{C}_8 \mathrm{H}_6$
C $C_9 H_{10}$
D $\mathrm{C}_7 \mathrm{H}_{16}$

The correct answer is:
$\mathrm{C}_7 \mathrm{H}_{16}$

Solution:
$C_7 H_{16} \quad\left(C_n H_{2 n+2}\right)$

Topic: Chemistry, Hydrocarbons, JEE Main
Which requires catalyst?

Options:
A $\mathrm{S}+\mathrm{O}_2 \rightarrow \mathrm{SO}_2$
B $2 \mathrm{SO}_2+\mathrm{O}_2 \rightarrow 2 \mathrm{SO}_3$
C $\mathrm{C}+\mathrm{O}_2 \rightarrow \mathrm{CO}_2$
D All

The correct answer is:
$2 \mathrm{SO}_2+\mathrm{O}_2 \rightarrow 2 \mathrm{SO}_3$

Solution:
${\underset{(\mathrm{S})}{2 \mathrm{SO}_2}+\underset{(\mathrm{g})}{\mathrm{O}_2}}{\xrightarrow[\text { Arbenton(promoter) }]{\mathrm{Pt} \text { Catalyst }}} 2 \mathrm{SO}_3(\mathrm{~g})$

Topic: Chemistry, Surface Chemistry, JEE Main
Which respect to an ore, Ellingham diagram helps to predict the feasibility of its

Options:
A Electrolysis
B Zone refining
C Vapour phase refining
D Thermal reduction

The correct answer is:
Thermal reduction

Solution:
Ellingham diagram is a graph showing temperature dependence of the stability of compounds. This analysis is used to evaluate the case of Reduction of metal oxides and sulphides. This diagram also used to predict the equilibrium temperature between a metal and its oxide.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main, JEE Main 2019 (08 Apr Shift 1)
Which salt on heating with conc. H2SO4 gives violet vapours?

Options:
A Iodide
B Nitrate
C Sulphate
D Bromide

The correct answer is:
Iodide

Solution:
KI+H2SO4Conc.âÎKHSO4+HI
âconc.â H 2 SO 4 + 2HIâ 2H 2 O + I 2 + SO 2 Violetâvapours

Topic: Chemistry, Practical Chemistry, JEE Main
Which series of reactions correctly represents the chemical relations related to iron and its compound?

Options:
A Fe→dilute H2SO4FeSO4→H2SO4,O2Fe2SO43→heatFe
B Fe→O2, heatFeO→dilute H2SO4FeSO4→heatFe
C Fe→Cl2, heatFeCl3→heat, airFeCl2→ZnFe
D Fe→O2, heatFe3O4→CO, 600℃FeO→CO, 700℃Fe

The correct answer is:
Fe→O2, heatFe3O4→CO, 600℃FeO→CO, 700℃Fe

Solution:
This is the blast furnace reaction. Fe→dilute H2SO4FeSO4→H2SO4, O2Fe2SO43→heatFe and Fe→O2, heatFeO→dilute H2SO4FeSO4→heatFe cannot be the answer since, FeSO4 on heating gives FeO and SO2.
Fe→Cl2, heatFeCl3→heat, airFeCl2→ZnFe is wrong because FeCl3, on heating in air, stays as Fe+3 and does not form FeCl2.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main, JEE Main 2014 (06 Apr)
Which set of coditions are correct for spontaneity of a electrochemical cell reaction?

Options:
A ΔG=0, ΔE=0
B ΔG=+ve, ΔE=+ve
C ΔG=-ve, ΔE=0
D ΔG=-ve, ΔE=+ve

The correct answer is:
ΔG=-ve, ΔE=+ve

Solution:
Spontaneity of cell indicates that the oxidation-reduction reaction is a spontaneous reaction for reduction at the cathode and oxidation at anode. For this ΔG must be negative.
ΔG=ΔH-TΔS ; ΔG=ΔE+PΔV-TΔS
For spontaneity ΔG=-ve
∵ΔG=-ve , ΔE=+ve

Topic: Chemistry, Thermodynamics (C), JEE Main
Which set of ions/solutes is responsible for maintaining the gradient of the medullary interstitium?

Options:
A Urea and HCl
B HCl and uric acid
C Urea, uric acid and hydrogen ion
D NaCl and urea

The correct answer is:
NaCl and urea

Solution:
The flow of filtrate in the two limbs of Henleâs loop is in opposite directions and thus forms a counter current. The flow of blood through the two limbs of vasa recta is also in a counter-current pattern. The proximity between the Henleâs loop and vasa recta, as well as the counter-current in them help in maintaining an increasing osmolarity towards the inner medullary interstitium, i.e., from 300 mOsmolLâ1 in the cortex to about 1200 mOsmolLâ1 in the inner medulla. This gradient is mainly caused by NaCl and urea.

Topic: Biology, Excretory Products and their Elimination, NEET
Which set of sonditions represents easiest way to liquefy a gas

Options:
A Low temperature and high pressure
B High temperature and low pressure
C Low temperature and low pressure
D High temperature and high pressure

The correct answer is:
Low temperature and high pressure

Solution:
Low temperature and high pressure
Gases can be liquified by compressing them at temperatures less than their critical temperature. The critical temperature is the highest temperature is the highest temperature at which a gas can be liquefied matter how much pressure is applied So, a low
temperature helps to reach the point where the gas can turn into a liquid. High pressure brings the gas particles closer together, which also aids in the liquefaction process.

Topic: Chemistry, States of Matter, JEE Main
Which set represent 1st order reactions out of (I), (II) and (III)?

where a = initial amount of reactant and x = amount of product at time t

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

The correct answer is:
I and II

Solution:
kt=2.303logâ¡aa-x
logâ¡aa-x=k2.303tâ¦.(I)
log( a )âlog( aâx )= k 2.303 t
log a−x =log a − k 2.303 t…. II
t 1 2 = 0.693 k â¦.( III )

Topic: Chemistry, Chemical Kinetics, JEE Main
Which show maximum valency

Options:
A Phosphorus
B Tin
C Antimony
D Bismuth

The correct answer is:
Phosphorus

Solution:
Phosphorus show + 5 valency

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which show maximum valency

Options:
A Phosphorus
B $\mathrm{Tin}$
C Antimony
D Bismuth

The correct answer is:
Phosphorus

Solution:
Phosphorus show + 5 valency

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which solution contains maximum number of \(H^{+}\) ion?

Options:
A \(0.1 \mathrm{M} \mathrm{HCl}\)
B \(0.1 \mathrm{M} \mathrm{NH}_4 \mathrm{Cl}\)
C \(0.1 \mathrm{M} \mathrm{NaHCO} 3\)
D \(0.1 \mathrm{M} \mathrm{CH}_3 \mathrm{COOH}\)

The correct answer is:
\(0.1 \mathrm{M} \mathrm{HCl}\)

Solution:
The \(\mathrm{HCl}\) is a strong acid and they lose easily \(\mathrm{H}^{+}\) in solution and hence contains maximum \(H^{+}\) ions in solution.

Topic: Chemistry, Ionic Equilibrium, JEE Main
Which species do not have ${ }^{s p^3}$ hybridization

Options:
A Ammonia
B Methane
C Water
D Carbon dioxide

The correct answer is:
Carbon dioxide

Solution:
$\mathrm{CO}_2$ is not $s p^3$ hybridised, it is $s p$ hybridised

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
Which species exhibits a plane of symmetry?

Options:
A
B
C
D

The correct answer is:

Solution:
Only this compound has plane of symmetry.

Topic: Chemistry, General Organic Chemistry, JEE Main
Which state of triply ionised beryllium (Be3+) has the same orbital radius as that of ground state of hydrogen?

Options:

The correct answer is:
2

Solution:
Radius of orbit of electron in nth excited state of hydrogen
r =Îµ0h2n2ÏmZe2
â´ rân2Z â¦(i)
â´ r1r2=n12n22ÃZ2Z1
But r1=r2
So, n22=n12 ÃZ2Z1
Here,
nâ¡ 1 = 1(ground state of hydrogen),
Zâ¡ 1 = 1(atomic number of hydrogen),
Zâ¡ 2 = 4(atomic number of beryllium)
â´ n22 = 1 2 Ã41
or n22 =4
or nâ¡ 2 = 2

Topic: Physics, Atomic Physics, JEE Main