datavorous/entrance-exam-dataset huggingface dataset:
Which one of the following equations specifies an isobaric process?
$[\mathrm{Q}=$ heat supplied $\Delta \mathrm{P}, \Delta \mathrm{V}$ and $\Delta \mathrm{T}$ are change in pressure, volume, and temperature respectively.]

Options:
A $\mathrm{Q}=0$
B $\Delta \mathrm{T}=0$
C $\Delta \mathrm{V}=0$
D $\Delta \mathrm{P}=0$

The correct answer is:
$\Delta \mathrm{P}=0$

Solution:
In isobaric process pressure remains constant, hence change in pressure is zero.

Topic: Physics, Thermodynamics, MHT CET, MHT CET 2021 (21 Sep Shift 1)
Which one of the following esters gets hydrolyzed most easily under alkaline conditions?

Options:
A
B
C
D

The correct answer is:

Solution:
EWG (Electron withdrawing group) increases reactivity towards nucleophilic substitution reaction. -NO2 is strong electron withdrawing group.

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which one of the following exhibits the large number of oxidation states?

Options:
A
$\mathrm{Ti}(22)$

B
$\mathrm{V}(23)$

C
$\mathrm{Cr}(24)$

D
$\operatorname{Mn}(25)$

The correct answer is:
$\operatorname{Mn}(25)$

Solution:
Maganese exhibits the large number of oxidation states. The most common oxidation states of $\mathrm{Mn}$ are $+2,+3$, $+4,+6$ and $+7$

Topic: Chemistry, d and f Block Elements, JEE Main, JEE Main 2014 (12 Apr Online)
Which one of the following explains light both as a stream of particles and as wave motion

Options:
A Diffraction
B $\lambda=h / p$
C Interference
D Photoelectric effect

The correct answer is:
$\lambda=h / p$

Solution:
$\lambda=\frac{h}{p}$ or $\frac{h}{m v}$ or $\frac{h}{m c}$ de-Broglie equation.

Topic: Chemistry, Structure of Atom, JEE Main
Which one of the following forms propane nitrile as the major product?

Options:
A Ethyl bromide + alcoholic KCN
B Propyl bromide + alcoholic KCN
C Propyl bromide $+$ alcoholic AgCN
D Ethyl bromide $+$ alcoholic AgCN

The correct answer is:
Ethyl bromide + alcoholic KCN

Solution:
When ethyl bromide reacts with alcoholic KCN, propane nitrile is obtained as main product.
$\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Br}+\mathrm{Alc} . \mathrm{KCN} \longrightarrow \underset{\text { propane nitrile }}{\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{CN}}$

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main
Which one of the following forms propane nitrile as the major product?

Options:
A Ethyl bromide + alcoholic KCN
B Propyl bromide + alcoholic KCN
C Propyl bromide $+$ alcoholic AgCN
D Ethyl bromide $+$ alcoholic AgCN

The correct answer is:
Ethyl bromide + alcoholic KCN

Solution:
When ethyl bromide reacts with alcoholic KCN, propane nitrile is obtained as main product.
$\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Br}+\mathrm{Alc} . \mathrm{KCN} \longrightarrow \underset{\text { propane nitrile }}{\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{CN}}$

Topic: Chemistry, Haloalkanes and Haloarenes, KCET, KCET 2010
Which one of the following four graphs best depict the variation with $\mathrm{x}$ of the moment of inertia $\mathrm{I}$ of a uniform triangular lamina about an axis parallel to its base at a distance $x$ from it

Options:
A
B
C
D

The correct answer is:

Solution:
$\mathrm{I}=\mathrm{I}_{\mathrm{COM}}+\mathrm{Mx}^{2}$
First it will decrease because $\mathrm{x}$ is increasing and axis is coming closer to COM axis. After Passing COM axis, M \& I will again increase
$\Rightarrow \mathrm{I}$ is minimum about the axis passing through COM if we compare I about other parallel axis

Topic: Physics, Rotational Motion, JEE Main
Which one of the following function is not related to hormones of adrenal cortex of adrenal gland?

Options:
A It regulate the balance of water and electrolytes in human body.
B It stimulate RBC production or erythropoeisis.
C It maintain emergency situations or 3 'F' conditions.
D It suppresses the immune response/system.

The correct answer is:
It maintain emergency situations or 3 'F' conditions.

Solution:
The adrenal cortex is mesodermal in origin. The cortex consists of fatty, cholesterol-rich cells. These cells distinguish the cortex into three zones or regions.
(i) Zona glomerulosa: It is the outer part of the cortex (15% of the gland), which consists of small polyhedral cells. It secrets mineralocorticoids e.g., Aldosterone. Mineralocorticoids (aldosterone) hormone regulate the balance of water and electrolytes.
(ii) Zona fasciculata: It is the middle part of the cortex (50% of the gland). Which consists of large polyhedral cells. This part secrets glucocorticoid e.g., cortisone, corticosterone. Glucocorticoid hormone stimulate RBCs production and suppresses immune response/system.
(iii) Zona Reticularis: It is the inner part of the cortex (7% of the gland). In which the parallel cell cords of the zona fasciculata branched to form a loose anastomosing network. It secrets sex hormones.
Adrenal medullary/adrenaline hormones maintain emergency or 3 F conditions

Topic: Biology, Chemical Coordination and Integration, NEET
Which one of the following functional groups undergoes hydrolysis with alkali to yield an acid group?

Options:
A $-\mathrm{CN}$
B $-\mathrm{CHO}$
C $-\mathrm{COCH}_3$
D $-\mathrm{Br}$

The correct answer is:
$-\mathrm{CN}$

Solution:
Cyanides are hydrolysed either by alkali or acid to give carboxylic acid.

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which one of the following gases is reported to retard photosynthesis?

Options:
A CO
B CFCs
C CO2
D NO2

The correct answer is:
NO2

Solution:
According to NCERT only NO2 from the given options can retard the photosynthesis process in plants.

Topic: Chemistry, Environmental Chemistry, JEE Main, JEE Main 2021 (20 Jul Shift 2)
Which one of the following generally acts as an antagonist to gibberellins?

Options:
A Zeatin
B Ethylene
C ABA
D IAA

The correct answer is:
ABA

Solution:
Abscisic acid (ABA) is also called stress hormone. It is a mildly acidic growth hormone which functions as a general growth inhibitor by counteractig other hormones (auxin, gibberelliun, cytokinin) or reactions mediated by them. It causes stomatal closure, abscission of flower and fruits while gibberellin helps in opening of stomata and promote development of fruits.

Topic: Biology, Plant - Growth and Development, NEET, NEET 2012 (Mains)
Which one of the following gives amine on heating with amide?

Options:
A $\mathrm{Br}_{2}$ in aqueous $\mathrm{KOH}$
B $\mathrm{Br}_{2}$ on alcoholic $\mathrm{KOH}$
C $\mathrm{Cl}_{2}$ in sodium
D sodium in ether

The correct answer is:
$\mathrm{Br}_{2}$ in aqueous $\mathrm{KOH}$

Solution:
Hofmann bromamide reaction : this method is used for the preparation of any $1^{\circ}$ amine as well as aniline. During the reaction amide is treated with $\mathrm{Br}_{2}$ and alkali $(\mathrm{KOH})$ to get primary amine. This reaction is used to descend the series in which carbon atom is removed as carbonate ion $\left(\mathrm{CO}_{3}^{2-}\right)$ reaction is given as

Topic: Chemistry, Amines, JEE Main
Which one of the following gives the most stable Diazonium salt ?

Options:
A
B
C
D

The correct answer is:

Solution:
The diazonium salt formed by aromatic primary amines are more stable than aliphatic primary amines.

Topic: Chemistry, Amines, JEE Main, JEE Main 2021 (01 Sep Shift 2)
Which one of the following graphs between molar conductivity Λm versus C is correct?

Options:
A
B
C
D

The correct answer is:

Solution:
Conductivity depends primarily on three factors: (i) concentration of ions, (ii) Temperature (iii) type of substance.
In our case, temperature is assumed to be same. This leaves the deciding factor as the cations of both substances (since both have chloride ions)
K+ will have higher conductivity than Na+ since the degree of hydration for Na+ is greater which reduces its mobility.
Hence, KCl having higher conductivity.

Topic: Chemistry, Electrochemistry, JEE Main, JEE Main 2019 (10 Apr Shift 2)
Which one of the following graphs between molar conductivity Λm versus C is correct?

Options:
A
B
C
D

The correct answer is:

Solution:
Conductivity depends primarily on three factors: (i) concentration of ions, (ii) Temperature (iii) type of substance.
In our case, temperature is assumed to be same. This leaves the deciding factor as the cations of both substances (since both have chloride ions)
K+ will have higher conductivity than Na+ since the degree of hydration for Na+ is greater which reduces its mobility.
Hence, KCl having higher conductivity.

Topic: Chemistry, Electrochemistry, JEE Main
Which one of the following graphs correctly describes disruptive selection? When studying fitness level associated with body size?

Options:
A

B

C

D

The correct answer is:

Solution:
Disruptive selection occurs when an environmental change may produce selection pressure that favours two extreme characteristics. Selection acts on the phenotype, physical, biochemical and behavioural traits of an organism. It indirectly adapts a population to its environment by selecting and maintaining favourable genotypes in their give pool.

Topic: Biology, Evolution, JIPMER, JIPMER 2017
Which one of the following graphs is not correct for ideal gas?

d= Density, P= Pressure, T=Temperature

Options:
A I
B II
C IV
D III

The correct answer is:
II

Solution:
For ideal gas

PM = dRT

d=PMR1T

Graph between density versus 1/T should be straight line.

Graph between density versus P should be straight line.

So graph between d Vs T is not straight line.

Hence option II is wrong.

Topic: Chemistry, States of Matter, JEE Main, JEE Main 2020 (02 Sep Shift 1)
Which one of the following graphs represent the behaviour of an ideal gas at constant temperature?

Options:
A
B
C
D

The correct answer is:

Solution:
The ideal gas equation is,

pV=nRT

where

p→ Pressure of the gas and

V→ Volume of the gas.

For an ideal gas, pV= constant at constant temperature T, i.e., pV does not vary with V.

Topic: Physics, Thermodynamics, JEE Main
Which one of the following graphs represents correctly the variation of the gravitational field $(F)$ with the distance $(r)$ from the centre of a spherical shell of mass $M$ and radius $a$

Options:
A

B

C

D

The correct answer is:

Solution:
Intensity will be zero inside the spherical shell.
\(I=0\) upto \(r=a\) and \(I \propto \frac{1}{r^2}\) when \(r > a\)
Option D

Topic: Physics, Gravitation, JEE Main
Which one of the following graphs represents the behaviour of an ideal gas?

Options:
A

B

C

D

The correct answer is:

Solution:
According to Boyle's law, at constant temperature, the $p V$ relation will be constant. The $p V$ versus $p$ or $V$ graph will be a straight line parallel to $X$-axis.
Hence, the $p V$ versus $V$ graph is given by

Topic: Physics, Kinetic Theory of Gases, JEE Main
Which one of the following group-15 hydride is the strongest reducing agent ?

Options:
A AsH3
B BiH3
C PH3
D SbH3

The correct answer is:
BiH3

Solution:
When we go down the group, the size of the atom increase also the distance between the metal hydrogen bond increases in hydrides. So, the strength of the metal hydrogen bond decreases. A reducing agent is one that supplies a hydrogen atom. Among 15th group hydrides, BiH3 is strongest reducing agent.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main, JEE Main 2021 (22 Jul Shift 1)
Which one of the following groupings represents a collection of isoelectronic species? (At. nos,: 55, Br:35)

Options:
A
$\mathrm{N}^{3-}, \mathrm{F}^{-}, \mathrm{Na}^{+}$

B
$\mathrm{Be}, \mathrm{Al}^{3+}, \mathrm{Cl}^{-}$

C
$\mathrm{Ca}^{2+}, \mathrm{Cs}^{+}, \mathrm{Br}$

D
$\mathrm{Na}^{+}, \mathrm{Ca}^{2+}, \mathrm{Mg}^{2+}$

The correct answer is:
$\mathrm{N}^{3-}, \mathrm{F}^{-}, \mathrm{Na}^{+}$

Solution:
$\mathrm{N}^{3-}, \mathrm{F}^{-}$and $\mathrm{Na}^{+}$contain 10 electrons each.

Topic: Chemistry, Structure of Atom, JEE Main, JEE Main 2003
Which one of the following groupings represents a collection of isoelectronic species

Options:
A $\mathrm{Na}^{+}, \mathrm{Ca}^{2+}, \mathrm{Mg}^{2+}$
B $\mathrm{N}^3, \mathrm{~F}^{-}, \mathrm{Na}^{+}$
C $\mathrm{Be}^{\mathrm{Al}}, \mathrm{Al}^{3+}$
D $\mathrm{Ca}^{2+}, \mathrm{Cs}^{+}, \mathrm{Br}$

The correct answer is:
$\mathrm{N}^3, \mathrm{~F}^{-}, \mathrm{Na}^{+}$

Solution:
$\mathrm{N}^{3-}, \mathrm{F}^{-}$and $\mathrm{Na}^{+}$(These three ions have $\mathrm{e}^{-}=10$, hence they are isoelectronic)

Topic: Chemistry, Structure of Atom, JEE Main
Which one of the following groups of animals is bilaterally symmetrical and triploblastic ?

Options:
A Sponges
B Coelentrates (Cnidarians)
C Aschelminthes (round worms)
D Ctenophores

The correct answer is:
Aschelminthes (round worms)

Solution:
No Solution Available

Topic: Biology, Animal Kingdom, NEET, NEET 2009 (Mains)
Which one of the following groups of three animals each is correctly matched with their one characteristic morphological feature?

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

The correct answer is:
(4)

Solution:
No Solution Available

Topic: Biology, Animal Kingdom, NEET, NEET 2008 (Mains)
Which one of the following has a square planar geometry?

Options:
A
$\left[\mathrm{CoCl}_4\right]^{2-}$

B
$\left[\mathrm{FeCl}_4\right]^{2-}$

C
$\left[\mathrm{NiCl}_4\right]^{2-}$

D
$\left[\mathrm{PtCl}_4\right]^{2-}$

The correct answer is:
$\left[\mathrm{PtCl}_4\right]^{2-}$

Solution:
${ }_{27} \mathrm{Co}^{2+}$-$\mathrm{1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^7 4 s^0}$
As $\mathrm{Cl}^{-}$is weak field ligand so no pairing up.
Hence it is $sp^3$ hybridized giving tetrahedral geometry.
$\mathrm{Fe}^{2+}$-$\mathrm{1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^6 4 s^0}$
Due to $\mathrm{Cl}^{-}$, back pairing is not observed so it will be $\mathrm{sp}^3$ hybridized giving tetrahedral geometry.
$\mathrm{Ni}^{2+}-1 \mathrm{s}^2 2 \mathrm{s}^2 2 \mathrm{p}^6 3 \mathrm{s}^2 3 p^6 3 \mathrm{d}^8 4 \mathrm{s}^0$
Because weak ligand, back pairing is not observed so it will be $\mathrm{sp}^3$ i.e. tetrahedral geometry.
All the complexes of $\mathrm{Pt}^{2+}$ are square planar including those with weak field ligand such as halide ions thus (D) is correct.

Topic: Chemistry, Coordination Compounds, JEE Main
Which one of the following has a square planar geometry?

Options:
A
$\left[\mathrm{CoCl}_4\right]^{2-}$

B
$\left[\mathrm{FeCl}_4\right]^{2-}$

C
$\left[\mathrm{NiCl}_4\right]^{2-}$

D
$\left[\mathrm{PtCl}_4\right]^{2-}$

The correct answer is:
$\left[\mathrm{PtCl}_4\right]^{2-}$

Solution:
${ }_{27} \mathrm{Co}^{2+}$-$\mathrm{1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^7 4 s^0}$
As $\mathrm{Cl}^{-}$is weak field ligand so no pairing up.
Hence it is $sp^3$ hybridized giving tetrahedral geometry.
$\mathrm{Fe}^{2+}$-$\mathrm{1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^6 4 s^0}$
Due to $\mathrm{Cl}^{-}$, back pairing is not observed so it will be $\mathrm{sp}^3$ hybridized giving tetrahedral geometry.
$\mathrm{Ni}^{2+}-1 \mathrm{s}^2 2 \mathrm{s}^2 2 \mathrm{p}^6 3 \mathrm{s}^2 3 p^6 3 \mathrm{d}^8 4 \mathrm{s}^0$
Because weak ligand, back pairing is not observed so it will be $\mathrm{sp}^3$ i.e. tetrahedral geometry.
All the complexes of $\mathrm{Pt}^{2+}$ are square planar including those with weak field ligand such as halide ions thus (D) is correct.

Topic: Chemistry, Coordination Compounds, JEE Main, JEE Main 2007
Which one of the following has an optical isomer ?
(en = ethylenediamine)

Options:
A
$\left[\mathrm{Zn}(\mathrm{en})\left(\mathrm{NH}_3\right)_2\right]^{2+}$

B
$\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}$

C
$\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_4(\text { en })\right]^{3+}$

D
$\left[\mathrm{Zn}(\text { en })_2\right]^{2+}$

The correct answer is:
$\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}$

Solution:
Only option (2) is having non-super imposable mirror image $\&$ hence one optical isomer.

Topic: Chemistry, Coordination Compounds, JEE Main, JEE Main 2010
Which one of the following has haplontic life cycle?

Options:
A Wheat
B Funaria
C Polytrichum
D Ustilago

The correct answer is:
Ustilago

Solution:
No Solution Available

Topic: Biology, Plant Kingdom, NEET, NEET 2009 (Mains)
Which one of the following has largest ionic radius ?

Options:
A F-
B B3+
C O2-
D Li+

The correct answer is:
O2-

Solution:
With increase in +ve charge, size of cation decreases.
With increase in -ve charge, size of anion increases.
Across the period, ionic size, decreases.
So correct order is B3+ < Li+ < F- < O2-

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2014 (19 Apr Online)
Which one of the following has maximum genetic diversity in India?

Options:
A Tea
B Teak
C Mango
D Wheat

The correct answer is:
Wheat

Solution:
No Solution Available

Topic: Biology, Biodiversity and its Conservation, NEET, NEET 2009 (Mains)
Which one of the following has maximumnumber of unpaired electrons?

Options:
A $\mathrm{Mg}^{2+}$
B $\mathrm{Ti}^{3+}$
C $\mathrm{V}^{3+}$
D $\mathrm{Fe}^{2+}$

The correct answer is:
$\mathrm{Fe}^{2+}$

Solution:
$\mathrm{Mg}^{2+}=1 \mathrm{~s}^{2}, 2 \mathrm{~s}^{2}, 2 \mathrm{p}^{6}$ (No unpaired electrons)
$\mathrm{Ti}^{3+}=1 \mathrm{~s}^{2}, 2 \mathrm{~s}^{2}, 2 \mathrm{p}^{6}, 3 \mathrm{~s}^{2}, 3 \mathrm{p}^{6}, 4 \mathrm{~s}^{0}, 3 \mathrm{~d}^{1}$ (One unpaired electrons)
$\mathrm{V}^{3+}=1 \mathrm{~s}^{2}, 2 \mathrm{~s}^{2}, 2 \mathrm{p}^{6}, 3 \mathrm{~s}^{2}, 3 \mathrm{p}^{6}, 4 \mathrm{~s}^{0}, 3 \mathrm{~d}^{2}$ (Two unpaired electrons)
$\mathrm{Fe}^{2+}=1 \mathrm{~s}^{2}, 2 \mathrm{~s}^{2}, 2 \mathrm{p}^{6}, 3 \mathrm{~s}^{2}, 3 \mathrm{p}^{6}, 4 \mathrm{~s}^{0}, 3 \mathrm{~d}^{6}$ (Four unpaired electrons)
$\therefore \mathrm{Fe}^{2+}$ has highest number of unpaired electrons.

Topic: Chemistry, d and f Block Elements, JEE Main
Which one of the following has the minimum boiling point?

Options:
A
n-butane

B
isobutane

C
1- butene

D
1- butyne

The correct answer is:
isobutane

Solution:
No Solution Available

Topic: Chemistry, Hydrocarbons, JEE Main, JEE Main 2004
Which one of the following has the regular tetrahedral structure?

Options:
A
$\mathrm{XeF}_4$

B
$\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2^{-}}$

C
$\mathrm{BF}_4{ }^{-4}$

D
$\mathrm{SF}_4$

The correct answer is:
$\mathrm{BF}_4{ }^{-4}$

Solution:
Total no of valence electrons $=3+7 \times 4+1=32$
Total No of hybrid orbital $=4$
$\because$ Hybridisation $=\mathrm{sp}^3$

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main, JEE Main 2004
Which one of the following helps in absorption of phosphorus from soil by plants?

Options:
A Rhizobium
B Frankia
C Anabaena
D Glomus

The correct answer is:
Glomus

Solution:
Glomus is a genus of arbuscular mycorrhizal (AM) fungi. It helps in nutrient uptake mainly the absorption of phosphorus.

Topic: Biology, Mineral Nutrition, NEET, NEET 2011 (Screening)
Which one of the following hormones is not involved in sugar metabolism?

Options:
A Aldosterone
B Insulin
C Glucagon
D Cortisone

The correct answer is:
Aldosterone

Solution:
Corticoids, which regulate the balance of water and electrolytes in our body are called mineralocorticoids. Aldosterone is the main mineralocorticoids in our body. It is formed from zona glomerulosa. Aldosterone acts mainly at the renal tubules and stimulates the reabsorption of Na+ and water and excretion of K+ and phosphate ions. Thus, aldosterone helps in the maintenance of electrolytes, body fluid volume, osmotic pressure and blood pressure.

Topic: Biology, Chemical Coordination and Integration, NEET, NEET 2015 (Phase 2)
Which one of the following hormones though synthesized elsewhere, is stored and release by the master gland?

Options:
A Luteinizing hormone
B Prolactin
C Melanocyte stimulating hormone
D Antidiuretic hormone

The correct answer is:
Antidiuretic hormone

Solution:
Neurohypophysis (pars nervosa) also known as posterior pituitary, stores and releases two hormones called oxytocin and vasopressin, which are actually synthesized by the hypothalamus and are transported axonally to the neurohypophysis.

Oxytocin acts on the smooth muscles of our body and stimulates their contraction. In females, it stimulates a vigorous contraction of the uterus at the time of childbirth, and milk ejection from the mammary gland.

Vasopressin acts mainly at the kidney and stimulates resorption of water and electrolytes by the distal tubules and thereby reduces the loss of water through urine (diuresis). Hence, it is also called anti-diuretic hormone (ADH).

Topic: Biology, Chemical Coordination and Integration, NEET, NEET 2015 (Phase 2)
Which one of the following human organs is often called the 'graveyard' of RBCs?

Options:
A Gall bladder
B Kidney
C Spleen
D Liver

The correct answer is:
Spleen

Solution:
The average life span of human RBCs is 120 days. The aged RBCs attract autoantibodies after which they are attached by macrophages in liver and spleen. Spleen is also called as graveyard of RBCs. The process of destruction of RBCs is called haemolysis. About 2.5 million RBCs destroyed every second in body.

Topic: Biology, Body Fluids and Circulation, NEET, NEET 2012 (Mains)
Which one of the following in birds, indicates their reptilian ancestry?

Options:
A Eggs with a calcareous shell
B Scales on their hind limbs
C Four-chambered heart
D Two special chambers crop and gizzard in their digestive tract

The correct answer is:
Scales on their hind limbs

Solution:
No Solution Available

Topic: Biology, Animal Kingdom, NEET, NEET 2008 (Mains)
Which one of the following involves nucleophilic addition?

Options:
A Kolbe's reaction of phenol
B Williamson synthesis of ethers
C Reimer-Tiemann reaction of phenol
D Aldol formation from ethanol

The correct answer is:
Aldol formation from ethanol

Solution:
Aldehydes and ketones show nucleophilic addition during aldol formation from alcohols.

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Which one of the following is a bijective function on the set of real numbers

Options:
A $2 x-5$
B $|x|$
C $x^2$
D $x^2+1$

The correct answer is:
$2 x-5$

Solution:
$|x|$ is not one-one; $x^2$ is not one-one; $x^2+1$ is not one-one. But $2 x-5$ is one-one because $f(x)=f(y) \Rightarrow 2 x-5=2 y-5 \Rightarrow x=y$ Now $f(x)=2 x-5$ is onto. $\therefore f(x)=2 x-5$ is bijective.

Topic: Mathematics, Functions, JEE Main
Which one of the following is a chain growth polymerisation?

Options:
A
Nucleic acid

B
Polystyrene

C
Protein

D
Starch

The correct answer is:
Polystyrene

Solution:
Polystyrene is a chain growth polymer.

Topic: Chemistry, Polymers, JEE Main, JEE Main 2012 (07 May Online)
Which one of the following is a hydrophobic sol

Options:
A Starch solution
B Gum solution
C Protein solution
D Arsenic sulphide solution

The correct answer is:
Arsenic sulphide solution

Solution:
Correct option is 4. Arsenic sulphide solution
Hydrophobic materials are used for oil removal from water, the management of oil spills, and chemical separation processes to remove non-polar substances from polar compounds.
Thus Arsenic sulphide sol is hydrophobic in nature.

Topic: Chemistry, Surface Chemistry, JEE Main
Which one of the following is a living fossil?

Options:
A Cycas
B moss
C Saccharomyces
D Spirogyra

The correct answer is:
Cycas

Solution:
Cycas is called a Living Fossil because Cycads are one of the oldest forms of plant life; they were here long, long before dinosaurs stomped the Earth and have remained basically unaffected.

Topic: Biology, Plant Kingdom, NEET, NEET 2004