datavorous/entrance-exam-dataset huggingface dataset:
Which of the following has highest concentration of PAN?

Options:
A Smoke
B Ozone
C Photochemical smog
D Reducing smog

The correct answer is:
Photochemical smog

Solution:
The main component of photochemical smog is peroxyacetyl nitrate, (PAN). The other components are ozone, nitric oxide, acrolein and formaldehyde.

Topic: Chemistry, Environmental Chemistry, AIIMS, AIIMS 2014
Which of the following has highest electrode potential

Options:
A $\mathrm{Be}$
B $\mathrm{Mg}$
C Ca
D $B a$

The correct answer is:
$\mathrm{Be}$

Solution:
Be has highest electrode potential

Topic: Chemistry, s Block Elements, JEE Main
Which of the following has highest Ka value?

Options:
A
B
C
D

The correct answer is:

Solution:
Acidic strength∝−I effect ∝  K a
Also (−I) power decreases as distance increases

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which of the following has highly acidic hydrogen?

Options:
A
B
C
D

The correct answer is:

Solution:
Acidic hydrogen is a hydrogen atom in an acid that dissociates to generate a positive ion.

After removal of H+ion, the negative charge is formed. The more stable the negative charge, the more will be the acidic strength.

Due to cross conjugation of negative charge, it is
most stabilised anion.

Hence, the answer is option D.

Topic: Chemistry, General Organic Chemistry, JEE Main, JEE Main 2024 (27 Jan Shift 1)
Which of the following has least bond energy?

Options:
A $\mathrm{N}_{2}^{2-}$
B $\mathrm{N}_{2}$
C $\mathrm{N}_{2}^{+}$
D $\mathrm{N}_{2}$

The correct answer is:
$\mathrm{N}_{2}$

Solution:
$\begin{aligned} \mathrm{N}_{2}^{2-}=K K^{\prime} \sigma 2 s^{2}, \sigma 2 s^{2}, \sigma 2 p_{z}^{2}, \pi 2 p_{x}^{2}, \approx \pi & 2 p_{y}^{2} \\ & \pi 2 p_{x}^{2} \end{aligned}$
$\begin{aligned} \therefore \text { Bond order } &=\frac{N_{b}-N_{a}}{2} \\ &=\frac{8-4}{2}=2 \end{aligned}$
(b) $\mathrm{N}_{2}^{-}=K K^{\prime} \sigma 2 \mathrm{~s}^{2}, \sigma 2 \mathrm{~s}^{2}, \sigma 2 p_{z}^{2}, \pi 2 p_{x}^{2}=\pi 2 p_{y}^{2}$
Bond order $=\frac{8-3}{2}=2.5$
(c) $\mathrm{N}_{2}^{+}=K K^{\prime} \sigma 2 s^{2} \sigma 2 s^{2}, \pi 2 p_{x}^{2}=\pi 2 p_{y}^{2}, \sigma 2 p_{z}^{1}$
Bond order $=\frac{7-2}{2}=2.5$
(d) $\mathrm{N}_{2}=K K^{\prime} \sigma 2 s^{2}, \sigma^{\dagger} 2 s^{2}, \pi 2 p_{x}^{2}=\pi 2 p_{y}^{2}, \sigma 2 p_{z}^{2}$
Bond order $=\frac{8-2}{2}=3$
$\because$ Bond energy $\propto \frac{1}{\text { Bond order }}$
$\therefore \mathrm{N}_{2}$ has least bond energy.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
Which of the following has least tendency to liberate H2 from mineral acids?

Options:
A Cu
B Mn
C Ni
D Zn

The correct answer is:
Cu

Solution:
Element M	E⊝/V

Mn	-1.18

Ni	-0.25

Cu	0.34

Zn	-0.76

As we can see that Copper is least electropositive metal among the given options. So, it does not react with dilute sulphuric acid or other mineral acids, liberating hydrogen because copper is lower in electrochemical series than hydrogen. All other metals will react with mineral acids to liberate hydrogen gas.

Topic: Chemistry, d and f Block Elements, JEE Main, JEE Main 2022 (28 Jul Shift 1)
Which of the following has longest CâO bond length? (Free CâO bond length in CO is 1.128 â A o ).

Options:
A NiCO4
B Co CO 4 −
C FeCO42-
D Mn CO 6 +

The correct answer is:
FeCO42-

Solution:
Metal carbon bond in metal carbonyls possess both Ï and Ï character. MâC Ï bond is formed by donation of a pair of electrons from filled orbital of metal into vacant antibonding Ï orbital of CO . CO bond length increases if M has more tendency to donate lone pair.
Tendency to donate lone pair is Fe 2â > Co â >Ni> Mn +

Topic: Chemistry, Coordination Compounds, JEE Main
Which of the following has maximum number of molecules

Options:
A $16 \mathrm{gm}$ of $\mathrm{O}_2$
B $16 \mathrm{gm}$ of $\mathrm{NO}_2$
C $7 \mathrm{gm}$ of $\mathrm{N}_2$
D $2 \mathrm{gm}$ of $\mathrm{H}_2$

The correct answer is:
$2 \mathrm{gm}$ of $\mathrm{H}_2$

Solution:
$2 \mathrm{gm}$. Hydrogen has maximum number of molecules than others.

Topic: Chemistry, Solutions, JEE Main
Which of the following has popularised the PCR (Polymerase Chain Reaction)?

Options:
A
Easy availability of DNA template

B
Availability of synthetic primers

C
Availability of cheap deoxyribonucleotides

D
Availability of 'Thermostable' DNA polymerase

The correct answer is:
Availability of 'Thermostable' DNA polymerase

Solution:
W. The amplification of specific DNA sequences is carried out in vitro called the Polymerase Chain Reaction (PCR). Such repeated amplification is achieved by the use of a thermostable DNA polymerase (isolated from a bacterium, Thermus aquaticus), which remains active and stable during the high temperature and later induce denaturation of doublestranded DNA.

Topic: Biology, Biotechnology - Principles and Processes
Which of the following has $\mathrm{S}-\mathrm{S}$ bond?

Options:
A $\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_6$
B $\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_7$
C $\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_8$
D Mustard gas

The correct answer is:
$\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_6$

Solution:
Only $\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_6$ (thionic acid) contains $\mathrm{S}-\mathrm{S}$ bond. Its structure is

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following has smaller size

Options:
A $\mathrm{H}$
B $\mathrm{He}^{+}$
C ${ }_1 H^2$
D $L i^{2+}$

The correct answer is:
$L i^{2+}$

Solution:
Lithium-ion is the smallest one because here protons are more than electrons. Protons attract electrons to come closer to the nucleus. So, it reduces its size and this size is less than that of a Hydrogen atom.
So Lithium-ion is the smallest.

Topic: Chemistry, s Block Elements, JEE Main
Which of the following has smallest radius?

Options:
A 1s2,2s22p6,3s2
B 1s2,2s22p6,3s23p1
C 1s2,2s22p6,3s23p5
D 1s2,2s22p6,3s23p3

The correct answer is:
1s2,2s22p6,3s23p5

Solution:
All the elements are of the same periods because all have the equal number of shell. In a period, the size of atom decreases as we from left to right,.i.e., from A to B to D to C. Hence, element corresponding to C is smallest in the size.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main
Which of the following has statocyst as balancing organ?

Options:
A Aurelia
B Taenia
C Pleurobrachia
D Ascaris

The correct answer is:
Pleurobrachia

Solution:
The largest single sensory feature is the aboral organ (at the opposite end from the mouth). Its main component is a statocyst, a balance sensor consisting of a statolith, a tiny grain of calcium carbonate, supported on four bundles of cilia, called "balancers", that sense its orientation.

Topic: Biology, Animal Kingdom, NEET
Which of the following has the highest moment of inertia when each of them has the same mass and the same outer radius

Options:
A a ring about its axis, perpendicular to the plane of the ring
B a disc about its axis, perpendicular to the plane of the ring
C a solid sphere about one of its diameters
D a spherical shell about one of its diameters

The correct answer is:
a ring about its axis, perpendicular to the plane of the ring

Solution:
The correct option is A A ring about its axis, perpendicular to the plane of the ring.
(a) Moment of inertia of a ring about its axis and perpendicular to its plane $=M r^2$
(b) Moment of inertia of a disc about its axis and perpendicular to its plane $=\frac{1}{2} M r^2=0.5 M r^2$
(c) Moment of inertia of a solid sphere about one of its diameter
$=\frac{2}{5} \mathrm{Mr}^2=0.4 \mathrm{Mr}^2$
(d) Moment of inertia of a spherical shell about one of its diameter
$=\frac{2}{3} M^2=0.66 M r^2$
Therefore, the moment of inertia of the ring is highest.

Topic: Physics, Rotational Motion, JEE Main
Which of the following has the highest moment of inertia when each of them has the same mass and the same radius?

Options:
A A ring about any of its diameter
B A disc about any of its diameter
C A hollow sphere about any of its diameter
D A solid sphere about any of its diameter

The correct answer is:
A hollow sphere about any of its diameter

Solution:
Let M and $\mathrm{R}$ be the mass and radius respectively.
Moment of inertia of a ring about any of its diameter is $I_{\text {ring }}=\left.\frac{1}{2} M R^2\right|_{\text {Moment of }}$ inertia of a disc about any of its diameter is $\left.I_{\text {disc }}=\frac{1}{4} M R^2 \right\rvert\,$
Moment of inertia of a hollow sphere about any of its diameter is $\left.I_{\text {hellow sphere }}=\frac{2}{3} M R^2 \right\rvert\,$
Moment of inertia of a solid sphere about any of its diameter is $\left.I_{\text {solid sphere }}=\frac{2}{5} M R^2 \right\rvert\,$
Thus, $I_{\text {hollow sphere }} \mid \mathrm{s}$ largest.

Topic: Physics, Rotational Motion, JEE Main
Which of the following has the highest nucleophilicity

Options:
A $F^{-}$
B $\mathrm{OH}^{-}$
C $\mathrm{CH}_3^{-}$
D $\mathrm{NH}_2$

The correct answer is:
$\mathrm{CH}_3^{-}$

Solution:
$\mathrm{CH}_3^{-}$has the highest nucleophilicity.

Topic: Chemistry, General Organic Chemistry, JEE Main
Which of the following has the largest gametophyte?

Options:
A Funaria
B Selaginella
C Pinus
D Oryza

The correct answer is:
Funaria

Solution:
Bryophyte has the largest multicellular free-living photosynthetic gametophyte. In Pteridophyta main plant body is sporophyte and gametophyte is small. In gymnosperm and angiosperm, the main plant body is sporophyte and gametophyte is highly reduced.

Topic: Biology, Plant Kingdom, NEET
Which of the following has the largest number of atoms?

Options:
A $1 \mathrm{~g}$ of $\mathrm{Ag}$
B $1 \mathrm{~g}$ of $\mathrm{Fe}$
C $1 \mathrm{~g}$ of $\mathrm{Cl}_{2}$
D $1 \mathrm{~g}$ of $\mathrm{Mg}$

The correct answer is:
$1 \mathrm{~g}$ of $\mathrm{Mg}$

Solution:
Hint:
Number of atoms of $\mathrm{Ag}=\frac{1}{108} \times \mathrm{N}_{\mathrm{A}}=0.009 \mathrm{~N}_{\mathrm{A}}$
Number of atoms of $\mathrm{Fe}=\frac{1}{56} \times \mathrm{N}_{\mathrm{A}}=0.0178 \mathrm{~N}_{\mathrm{A}}$
Number of atoms of $\mathrm{Cl}_{2}=\frac{1}{71} \times 2 \times \mathrm{N}_{\mathrm{A}}=0.028 \mathrm{~N}_{\mathrm{A}}$
Number of atoms of $\mathrm{Mg}=\frac{1}{24} \mathrm{~N}_{\mathrm{A}}=0.041 \mathrm{~N}_{\mathrm{A}}$ [largest]

Topic: Chemistry, Some Basic Concepts of Chemistry, JEE Main
Which of the following has the largest number of moles?

Options:
A 8 g of oxygen atoms
B 16 g of oxygen gas
C 14 g of nitrogen gas N2
D All have the same number of moles

The correct answer is:
All have the same number of moles

Solution:
∵ n=(actual mass) (molar mass)

(a) n=wm=816=12 mole

(b) n=1632=12 mole

(c) n=1428=12 mole

(d) Thus, all have the same number of moles.

Topic: Chemistry, Some Basic Concepts of Chemistry, JEE Main
Which of the following has the maximum number of unpaired ' $d$ ' electrons?

Options:
A $\mathrm{Zn}^{2+}$
B $\mathrm{Fe}^{2+}$
C $\mathrm{Ni}^{3+}$
D $\mathrm{Cu}^{+}$

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

Solution:
$$
\begin{aligned}
\mathrm{Zn}(30)=& {[\mathrm{Ar}] 3 \mathrm{~d}^{10}, 4 \mathrm{~s}^{2} } \\
\mathrm{Zn}^{2+} &=[\mathrm{Ar}] 3 \mathrm{~d}^{10} \text { (no unpaired electron) } \\
\mathrm{Fe}(26) &=[\mathrm{Ar}] 3 \mathrm{~d}^{6}, 4 \mathrm{~s}^{2} \\
\mathrm{Fe}^{2+} &=[\mathrm{Ar}] 3 \mathrm{~d}^{6} \text { (four unpaired electrons) }
\end{aligned}
$$
$\begin{aligned} \mathrm{Ni}(28) &=[\mathrm{Ar}] 3 \mathrm{~d}^{8}, 4 \mathrm{~s}^{2} \\ \mathrm{Ni}^{3+} &=[\mathrm{Ar}] 3 \mathrm{~d}^{7} \text { (three unpaired electrons) } \end{aligned}$
$$
\begin{aligned}
\mathrm{Cu}(29) &=[\mathrm{Ar}] 3 \mathrm{~d}^{10}, 4 \mathrm{~s}^{1} \\
\mathrm{Cu}^{+} &=[\mathrm{Ar}] 3 \mathrm{~d}^{10} \text { (no unpaired electron) }
\end{aligned}
$$

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main
Which of the following has the shortest C-Cl bond?

Options:
A Cl-CH=CH2
B Cl-CH=CH-NO2
C Cl-CH=CH-CH3
D Cl-CH=CH-OCH3

The correct answer is:
Cl-CH=CH-NO2

Solution:
Due to âM effect of â NO 2 and + M effect of Cl more D.B. character between C â Cl bond. So shortest bond length.

Topic: Chemistry, General Organic Chemistry, JEE Main, JEE Main 2020 (09 Jan Shift 2)
Which of the following has the square planar structure?

Options:
A
$\mathrm{XeF}_4$

B
$\mathrm{NH}_4^{+}$

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

D
$\mathrm{CCl}_4$

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

Solution:
$\mathrm{XeF}_4$ has square planar structure, while $\mathrm{NH}_4^{+}, \mathrm{BF}_4^{-}$and $\mathrm{CCl}_4$ have tetrahedral structure.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main, JEE Main 2012 (19 May Online)
Which of the following has unpaired electron(s)?

Options:
A O 2 -
B N 2 2 +
C O 2 2 -
D N2

The correct answer is:
O 2 -

Solution:
The Molecular orbital electronic configurations are
O 2 â âÏ1 s 2 < Ï * 1 s 2 <Ï2 s 2 < Ï * 2 s 2 <Ï2 p z 2 <Ï2 p x 2 =Ï2 p y 2 < Ï * 2 p x 2 = Ï * 2 p y 1 (unpaired electron)
N 2 2+ âÏ1 s 2 < Ï * 1 s 2 <Ï2 s 2 < Ï * 2 s 2 <Ï2 p x 2 =Ï2 p y 2 <Ï2 p z 0
O 2 2â âÏ1 s 2 < Ï * 1 s 2 <Ï2 s 2 < Ï * 2 s 2 <Ï2 p z 2 <Ï2 p x 2 =Ï2 p y 2 < Ï * 2 p x 2 = Ï * 2 p y 2
N 2 âÏ1 s 2 < Ï * 1 s 2 <Ï2 s 2 < Ï * 2 s 2 <Ï2 p x 2 =Ï2 p y 2 <Ï2 p z 2

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main, JEE Main 2014 (09 Apr Online)
Which of the following has zero dipole moment?

Options:
A 1,1 -dichloromethane
B cis -1,2 -dichloroethene
C trans -1,2 -dichloroethene
D 1 -chloroethane

The correct answer is:
trans -1,2 -dichloroethene

Solution:
No Solution available

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
Which of the following have same number of significant figures?
(A) 0.00253
(B) 1.0003
(C) 15.0
(D)163
Choose the correct answer from the options given below

Options:
A A, B and C only
B C and D only
C B and C only
D A, C and D only

The correct answer is:
A, C and D only

Solution:
All nonzero digits are significant. All zeros that are found between nonzero digits are significant. Leading zeros (to the left of the first nonzero digit) are not significant. Trailing zeros for a whole number that ends with a decimal point are significant.The number of significant figures of the given numbers are as follows:
Numbers No. of significant figures
(A) 0.00253 3
(B) 1.0003 5
(C) 15.0 3
(D) 163 3
∴ (A), (C) and (D) have the same number of significant figures.

Topic: Chemistry, Some Basic Concepts of Chemistry, JEE Main, JEE Main 2023 (08 Apr Shift 2)
Which of the following helps in ascent of sap?

Options:
A Root pressure
B Transpiration
C Capillarity
D All of these

The correct answer is:
All of these

Solution:
Water is mainly absorbed by roots which goes upwards so as to replace water loss in transpiration and to be used in photosynthesis. This upward movement of water from roots to leaves through stem against force of gravity is called ascent of sap. Different theories have been put forward in support of ascent of sap. They include root pressure theory, capillary theory and transpiration pull theory. Root pressure is developed when rate of absorption is more than rate of transpiration and so water is pushed up in the tracheary elements. Capillary force theory was given by Bohm, according to which xylem vessels act as minute capillaries and water rises in these capillaries due to capillary action or surface tension. According to transpiration pull theory by Dixon and Jolly, due to water loss by transpiration suction pressure is increased and water is absorbed from adjacent xylem vessels of leaves and thus sap in under tension.

Topic: Biology, Transport in Plants, AIIMS, AIIMS 2007
Which of the following helps in maintenance of the pressure gradient in sieve tubes?

Options:
A Albuminous cells
B Sieve cells
C Phloem parenchyma
D Companion cells

The correct answer is:
Companion cells

Solution:
The companion cells help in maintaining the pressure gradient in the sieve tubes

Topic: Biology, Transport in Plants, NEET, NEET 2024 (Re-NEET)
Which of the following hormonal disorder is characterised by mental retardation, stunted growth, low intelligence quotient and deaf mutismin in growing baby?

Options:
A Cretinism
B Myxedema
C Goitre
D All of these

The correct answer is:
Cretinism

Solution:
Hypothyroidism during pregnancy causes defective development and maturation of the growing baby leading to mental retardation, stunted growth, low intelligence quotient, abnormal skin and deaf mutism etc. This is called cretinism disease, which mainly occurs in growing children.

Topic: Biology, Chemical Coordination and Integration, NEET
Which of the following hormone helps in maintaining body temperature, metabolism, pigmentation, and defense capabilities?

Options:
A Melatonin
B Melanin
C Thymosin
D Calcitonin

The correct answer is:
Melatonin

Solution:
The pineal gland is located on the dorsal side of forebrain. Pineal secretes a hormone called melatonin. Melatonin plays a very important role in the regulation of a 24-hour (diurnal) rhythm of our body. For example, it helps in maintaining the normal rhythms of sleep-wake cycle, body temperature. In addition, melatonin also influences metabolism, pigmentation, the menstrual cycle as well as our defense capability.

Topic: Biology, Chemical Coordination and Integration, NEET
Which of the following hormone, in combination with auxin, stimulates cell division in plants and determines the course of differentiation mainly?

Options:
A Ethylene
B IAA
C Gibberellins
D Cytokinin

The correct answer is:
Cytokinin

Solution:
The cytokinin hormones promote cell division and tissue growth and depend upon the presence of auxins to determine the extent of their activity. When the ratio of cytokinins to auxins is relatively high, stem and leaf growth is stimulated. Auxins and cytokinins are the best documented as impinging directly on cell cycle control.

Topic: Biology, Plant - Growth and Development, NEET
Which of the following hormone increases the calcium level of blood?

Options:
A Parathyroid hormone
B Noradrenaline
C Corticosteroids
D Aldosterone

The correct answer is:
Parathyroid hormone

Solution:
The parathyroid glands produce parathyroid hormone. This hormone helps maintain an appropriate balance of calcium in the bloodstream.
Functions of Parathyroid hormone (PTH):
1. PTH increases the process of bone resorption or dissolution (demineralisation) of bone.
2. PTH stimulates the reabsorption of Ca2+ by the renal tubules.
3. PTH increases absorption of Ca2+ from the digested food.
4. All above actions of PTH increases the blood Ca2+ levels, thus PTH is a hypercalcemic hormone. PTH and TCT plays a significant role in maintaining the calcium balance in the body.

Topic: Biology, Chemical Coordination and Integration, NEET
Which of the following hormones are secreted by pars nervosa?

Options:
A Adrenaline and nor-adrenaline
B Vasopressin and somatostatin
C STH and prolactin
D Oxytocin & vasopressin

The correct answer is:
Oxytocin & vasopressin

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 neurohypophysis.

â¢ 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.

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

Topic: Biology, Chemical Coordination and Integration, NEET
Which of the following hormones contains iodine?

Options:
A Thyroxine
B Insuline
C Testosterone
D Adrenaline

The correct answer is:
Thyroxine

Solution:
Thyroxine contains iodine. Its structure is

Topic: Physics, Nuclear Physics, NEET, NEET 2009 (Mains)
Which of the following hormones has no control over gluconeogenesis?

Options:
A Insulin
B Glucagon
C Vasopressin
D Corticosterone

The correct answer is:
Vasopressin

Solution:
Gluconeogenesis is synthesis of Glucose from non- carbohydrate source like fats, proteins etc. This is a hormonal-mediated process. It occurs in liver mainly and in kidney too. Many hormones like glucagon, growth hormone and corticosterone have stimulatory effect while insulin has inhibitory effect on it. Vasopressin is released by posterior pituitary and its main function is maintaining the water and salt balance and thus it has no role on synthesis of glucose.

Topic: Biology, Chemical Coordination and Integration, NEET
Which of the following hormones is not a secretion product of human placenta?

Options:
A human chorionic gonadotropin
B prolactin
C estrogen
D progesterone.

The correct answer is:
prolactin

Solution:
Prolactin is secreted by anterior pituitary gland and cause production of milk in mammary glands. Placenta produce estrogen, progesterone, relaxin Human chorionic gonadotropin hormone (hCG) and Human placental lactogen (hPL).
Related Theory
Progesterone acts to maintain pregnancy by supporting the lining of the uterus (womb), which provides the environment for the foetus and the placenta to grow. estrogen is also produced by the placenta during pregnancy to help maintain a healthy pregnancy.
Caution
Circulating relaxin is secreted by the corpus luteum. The placenta, decidua, or both also produce relaxin, which does not enter the circulation but may act in an autocrine or paracrine fashion. hCG is a stimulus to luteal relaxin secretion.

Topic: Biology, Chemical Coordination and Integration, NEET, NEET 2004
Which of the following hormones is not a secretion product of the human placenta?

Options:
A Human chorionic gonadotropin
B Prolactin
C Estrogen
D Progesterone

The correct answer is:
Prolactin

Solution:
Human chorionic gonadotropin is released by synotiotrophoblesty. cells of the placenta. âEstrogen and progesterone are also released by placental cells to maintain pregnancy. Prolactin is secreted from anterior lobe of pituitary. Placenta secretes Human Placental Lactogenic Factor which prepare mammary glands to secrete milk.

Topic: Biology, Chemical Coordination and Integration, NEET
Which of the following hormones stimulates the reabsorption of electrolytes in the kidney?

Options:
A Arginine
B TSH
C ADH
D ACTH

The correct answer is:
ADH

Solution:
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 an anti-diuretic hormone (ADH).

Topic: Biology, Chemical Coordination and Integration, NEET
Which of the following hydrides of nitrogen is acidic in nature?

Options:
A NH3
B N3H
C N2H2
D N2H4

The correct answer is:
N3H

Solution:
The N3- has linear structure, because N+ in sp-hybridized. The weakly acidic nature of N3H is due to the fact that N3- is more resonance stabilized than N3H .

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following hydrogen bonds is the strongest?

Options:
A
$\mathrm{O}-\mathrm{H} \ldots \ldots \mathrm{N}$

B
$\mathrm{F}-\mathrm{H} \ldots \ldots \mathrm{F}$

C
$\mathrm{O}-\mathrm{H} \ldots \ldots . \mathrm{O}$

D
$\mathrm{O}-\mathrm{H} \ldots \ldots \mathrm{F}$

The correct answer is:
$\mathrm{F}-\mathrm{H} \ldots \ldots \mathrm{F}$

Solution:
The hydrogen bond in $\mathrm{HF}$ is strongest, because fluorine is the most electronegative element.
Thus, (B) is the correct option.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main, JEE Main 2007
Which of the following imparts green colour to the burner flame

Options:
A $\mathrm{B}(\mathrm{OMe})_3$
B $\mathrm{Na}(\mathrm{OMe})$
C $\mathrm{Al}(\mathrm{OPr})_3$
D $\operatorname{Sn}(\mathrm{OH})_2$

The correct answer is:
$\mathrm{B}(\mathrm{OMe})_3$

Solution:
Boric acid with methanol in presence of conc. $\mathrm{H}_2 \mathrm{SO}_4$ forms $\mathrm{B}(\mathrm{OMe})_3$ which burns with a green flame.

Topic: Chemistry, Practical Chemistry, JEE Main