datavorous/entrance-exam-dataset huggingface dataset:
Which of the following in second ion is more stable than the first

Options:
A
B
C
D

The correct answer is:

Solution:
(A) II : Acetylenic carbanion is more stable than vinylic carbanion
(B) I : Benzyl carbanion is more stable (4 resonating structures) than allyl carbanion (two resonating structures)
(C) II : See allyl carbanion is less stable than p-allyl carbanion.
(D) I : is aromatic and (II) is non aromatic.

Topic: Chemistry, General Organic Chemistry, JEE Main
Which of the following increases in magnitude as the atomic number of alkli metals increases?

Options:
A Electronegativity
B First ionisation energy
C Ionic radius
D Melting point

The correct answer is:
Ionic radius

Solution:
→ Ionic radius Li +  <  Na + <  K + <  Rb + <  Cs + ← Melting point / Ionisation Energy / Electronegativity Li > Na > K > Rb > Cs

Topic: Chemistry, s Block Elements, JEE Main
Which of the following intervals is a possible domain of the function $f(x)=\log _{\{x\}}[x]+\log _{[x]}\{x\}$, where $[x]$ is the greatest integer not exceeding $x$ and $\{x\}=x-[x]$ ?

Options:
A $(0,1)$
B $(1,2)$
C $(2,3)$
D $(3,5)$

The correct answer is:
$(2,3)$

Solution:
$\mathrm{x} \notin \mathrm{I} \quad \& \quad[\mathrm{x}]>1$
$\Rightarrow x \in(2,3)$ only option satisfy.

Topic: Mathematics, Functions, KVPY, KVPY 2011 (SB/SX)
Which of the following ion is expected to have highest value of molar conductivity at infinite dilution in the aqueous solution?

Options:
A Na+
B K+
C Ca2+
D H+

The correct answer is:
H+

Solution:
Among the cations H+ has the maximum conductivity due to grotthuss conduction.

Topic: Chemistry, Electrochemistry, JEE Main
Which of the following ionic/molecular species does not disproportionate in water at room temperature?

Options:
A NO2
B Cu+
C MnO42-
D Ca(OCl)Cl

The correct answer is:
Ca(OCl)Cl

Solution:
Here only Ca(OCl)Cl does not disproportionate in water at room temperature.
2NO 2  +  H 2 O→ HNO 3  +  HNO 2 → Disproportionation relation Room temp. HNO 3  + NO
2Cu(aq)+→R.T.Cu+Cu(aq)2+
CaOClCl→WaterCa2+aq+Cl-aq+OCl-aq

Topic: Chemistry, Redox Reactions, JEE Main
Which of the following ionic/molecular species does not disproportionate in water at room temperature?

Options:
A NO2
B Cu+
C MnO42-
D Ca(OCl)Cl

The correct answer is:
Ca(OCl)Cl

Solution:
2NO 2 â+â H 2 Oâ HNO 3 â+â HNO 2 â disproportionation HNO 3 â+âNO
2Cu + (aq) â R.T. Cuâ+â Cu 2+ (aq)
3 M +6 nO 4 2− (aq) → disproportionation 2 M +7 nO 4 −  (aq) +  M +4 nO 2  +  4OH −
Ca(OCl)Cl â water Ca 2+ (aq)â+â Cl â (aq)â+â OCl â (aq)

Topic: Chemistry, Redox Reactions, JEE Main
Which of the following ions are actively secreted into the filtrate by tubular cells of nephron during urine formation?

Options:
A NH3,Â H+,Â Na+
B Na+,Â K+,Â NH3
C K+,Â H+,Â HCO3-
D K+, NH3, H+

The correct answer is:
K+, NH3, H+

Solution:
Tubular secretion is one of the step of urine formation which mainly occurs by cells of PCT and DCT of nephrons. The selective secretion of harmful and nitrogenous wastes such as K+,H+,NH3 , etc., from blood to filterate takes place by tubular cells of nephron.

Topic: Biology, Excretory Products and their Elimination, NEET
Which of the following ions does not liberate hydrogen gas on reaction with dilute acids?

Options:
A V2+
B Ti2+
C Mn2+
D Cr2+

The correct answer is:
Mn2+

Solution:
Mn2+ does not displace H2 from dilute acid because they are less reactive SRP value.

Given below are SRP values,
H2O|H2=-0.8277, Mn2+|Mn=-1.185 V

Topic: Chemistry, Electrochemistry, JEE Main, JEE Main 2017 (09 Apr Online)
Which of the following ions forms highly soluble hydroxide in water

Options:
A $K^{+}$
B $\mathrm{Zn}^{++}$
C $A l^{+++}$
D $\mathrm{Ca}^{++}$

The correct answer is:
$K^{+}$

Solution:
$K$ is highly soluble because of high hydration energy.

Topic: Chemistry, s Block Elements, JEE Main
Which of the following ions has the highest magnetic moment

Options:
A Ti3+
B Sc3+
C Mn2+
D Zn2+

The correct answer is:
Mn2+

Solution:
Ti3+ → 3d14s0 ; Sc3+ → 3d0 ; Mn2+ → 3d54s0 ; Zn2+ → 3d104s0
In Mn2+ number of unpaired d e-=5 . So it has maximum magnetic moment according to the formula. μ=n(n+2)

Topic: Chemistry, d and f Block Elements, JEE Main
Which of the following ions has the maximum magnetic moment ?

Options:
A
$\mathrm{Mn}^{+2}$

B
$\mathrm{Fe}^{+2}$

C
$\mathrm{Ti}^{+2}$

D
$\mathrm{Cr}^{+2}$

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

Solution:
$\mathrm{Mn}^{2+}$ has the maximum number of unpaired electrons $(5)$ and therefore has maximum moment.

Topic: Chemistry, d and f Block Elements, JEE Main, JEE Main 2002
Which of the following ions have maximum hydration energy?

Options:
A Sr+2
B Ca+2
C Mg+2
D Be+2

The correct answer is:
Be+2

Solution:
Hydration energy ∝  1 size of ion

Topic: Chemistry, s Block Elements, JEE Main
Which of the following ions is colourless in solution?

Options:
A $\mathrm{V}^{3+}$
B $\mathrm{Cr}^{3+}$
C $\mathrm{Co}^{2+}$
D $\mathrm{Sc}^{3+}$

The correct answer is:
$\mathrm{Sc}^{3+}$

Solution:
$\mathrm{V}(23)=[\mathrm{Ar}] 3 \mathrm{~d}^{3}, 4 s^{2}$
$\mathrm{V}^{3+}=[\mathrm{Ar}] 3 d^{2}, 4 s^{0} \quad$ (two unpaired electrons)
$$
\begin{array}{l}
\operatorname{Cr}(24)=[\mathrm{Ar}] 3 d^{5}, 4 s^{1} \\
\mathrm{Cr}^{3+}=[\mathrm{Ar}] 3 d^{3}, 4 s^{0}
\end{array}
$$
(three unpaired electrons)
$$
\operatorname{Co}(27)=[\mathrm{Ar}] 3 d^{7}, 4 s^{2}
$$
$$
\mathrm{Co}^{2+}=[\mathrm{Ar}] 3 \mathrm{~d}^{7}, 4 s^{0}
$$
(three unpaired electrons)
$$
\mathrm{Sc}(21)=[\mathrm{Ar}] 3 d^{7}, 4 s^{2}
$$
$\mathrm{Sc}^{3+}=[\mathrm{Ar}] 3 d^{0}, 4 s^{0} \quad$ (no unpaired electrons)
Thus, in $\mathrm{Sc}^{3+}$ no unpaired $d$ -electron is present. Hence, no $d-d$ transition is possible and it is colourless ion.

Topic: Chemistry, d and f Block Elements, JEE Main
Which of the following ions will cause hardness of sample water?

Options:
A \( \mathrm{Na}^{+} \)
B \( \mathrm{K}^{+} \)
C \( \mathrm{Ca}^{2+} \)
D \( \mathrm{Li}^{+} \)

The correct answer is:
\( \mathrm{Ca}^{2+} \)

Solution:
Water containing soluble bicarbonate, chloride, sulphate, etc. salts of calcium and magnesium is known as hard water. This type of water does not give lather with soap.

Water which does not contain such salts is known as soft water. This water forms lather with soap easily.

Topic: Chemistry, Hydrogen, JEE Main
Which of the following is a bactericidal antibiotic?

Options:
A Ofloxacin
B Tetracycline
C Chloramphenicol
D Erythromycin

The correct answer is:
Ofloxacin

Solution:
Ofloxacin is a bactericidal antibiotic which kills bacteria and all other given options are bacteria static which inhibit the growth of bacteria.

Topic: Chemistry, Chemistry in Everyday Life, JEE Main, JEE Main 2016 (10 Apr Online)
Which of the following is a bactericidal antibiotic?

Options:
A Ofloxacin
B Tetracycline
C Chloramphenicol
D Erythromycin

The correct answer is:
Ofloxacin

Solution:
Ofloxacin is a bactericidal antibiotic which kills bacteria and all other given options are bacteriastatic which inhibit the growth of bacteria.

Topic: Chemistry, Chemistry in Everyday Life, JEE Main
Which of the following is a biodegradable polymer?

Options:
A

B

C

D

The correct answer is:

Solution:
Nylon-2-Nylon-6
Polymer of glycine and amino caproic acid.

Topic: Chemistry, Polymers, JEE Main, JEE Main 2017 (09 Apr Online)
Which of the following is a biodegradable polymer?

Options:
A Cellulose
B PVC
C Nylon-6
D Polythene

The correct answer is:
Cellulose

Solution:
Cellulose is an example of biodegradable polymer because it can be easily degradable by various natural processes. PVC, Nylon-6 and Polythene cannot be degraded by various natural processes.

Topic: Chemistry, Polymers, JEE Main
Which of the following is a biradical?

Options:
A Phenyl
B Propenyl
C Vinylidene
D Ethylidyne

The correct answer is:
Vinylidene

Solution:

Topic: Chemistry, General Organic Chemistry, JEE Main
Which of the following is a carbohydrate?

Options:
A Glutamic acid
B Insulin
C Pectin
D Cholesterol

The correct answer is:
Pectin

Solution:
Pectin is a structural acidic heteropolysaccharide contained in the primary and middle lamella cell walls of terrestrial plants. Its main component is galacturonic acid, a sugar acid derived from galactose.

Topic: Chemistry, Biomolecules, NEET
Which of the following is a characteristic feature of the human cornea?

Options:
A It is secreted by the conjunctiva and glandular cells.
B It is also called a lacrimal gland, which secretes tears.
C Blood circulation is absent in the cornea.
D In old age, the cornea hardens and a white layer is deposited over it, which leads to the formation of a cataract.

The correct answer is:
Blood circulation is absent in the cornea.

Solution:
The outermost layer of the eye ball is fibrous in nature. Two - third part of this layer is opaque and lies inside the eye orbit and is known as sclera. The remaining one-third of the outer layer is transparent and bulges out to form the cornea. There is no supply of blood in cornea.

Topic: Biology, Neural Control and Coordination, NEET
Which of the following is a characteristic property of Plaster of Paris?

Options:
A It remains soft indefinitely
B It doesn't set with water
C It sets into a hard solid in a short time
D It dissolves in water

The correct answer is:
It sets into a hard solid in a short time

Solution:
Plaster of Paris has the characteristic property of setting into a hard solid in a relatively short time when mixed with water.

Topic: Chemistry, s Block Elements, NEET
Which of the following is a chronic respiratory disorder in which alveolar walls are damaged due to which respiratory surface is decreased?

Options:
A Asthma
B Emphysema
C Silicosis
D Pneumonia

The correct answer is:
Emphysema

Solution:
Emphysema is one of the main types of chronic obstructive pulmonary disease (COPD). It’s called “obstructive” because people with emphysema exhale as if something were obstructing the flow of air. There are multiple causes of emphysema, but smoking is by far the most common.

Topic: Biology, Breathing and Exchange of Gases, NEET
Which of the following is a colligative property

Options:
A Osmotic pressure
B Boiling point
C Vapour pressure
D Freezing point

The correct answer is:
Osmotic pressure

Solution:
Osmotic pressure is colligative property.

Topic: Chemistry, Solutions, JEE Main
Which of the following is a common donor atom in ligands

Options:
A Arsenic
B Nitrogen
C Oxygen
D Both (2) and (3)

The correct answer is:
Both (2) and (3)

Solution:
Both (2) and (3)

Topic: Chemistry, Coordination Compounds, JEE Main
Which of the following is a common use of calcium?

Options:
A Making batteries
B Strengthening bones and teeth
C Manufacturing explosives
D Producing lightweight alloys

The correct answer is:
Strengthening bones and teeth

Solution:
Calcium is an essential mineral for the formation and maintenance of bones and teeth in humans.

Topic: Chemistry, s Block Elements, NEET
Which of the following is a condensation polymer?

Options:
A Nylon 6, 6
B Neoprene
C Buna-S
D Teflon

The correct answer is:
Nylon 6, 6

Solution:
In the condensation polymerization reaction, the elimination of small molecules such as water, alcohol, hydrogen chloride takes place.

Nylon, a condensation polymer, is made of hexamethylene diamine and adipic acid.

Buna-S, Teflon and Neoprene are addition polymers.

Topic: Chemistry, Polymers, JEE Main, JEE Main 2019 (10 Apr Shift 1)
Which of the following is a contradiction?

Options:
A $(p \wedge q) \wedge \sim(p \vee q)$
B $p \vee(\sim p \wedge q)$
C $(p \Rightarrow q) \Rightarrow p$
D None of these

The correct answer is:
$(p \wedge q) \wedge \sim(p \vee q)$

Solution:
$$
\begin{array}{|c|c|c|c|c|c|}
\hline p & q & p \wedge q & p \vee q & \sim(p \vee q) & (p \wedge q) \wedge \sim(p \vee q) \\
\hline \mathrm{T} & \mathrm{T} & \mathrm{T} & \mathrm{T} & \mathrm{F} & \mathrm{F} \\
\hline \mathrm{T} & \mathrm{F} & \mathrm{F} & \mathrm{T} & \mathrm{F} & \mathrm{F} \\
\hline \mathrm{F} & \mathrm{T} & \mathrm{F} & \mathrm{T} & \mathrm{F} & \mathrm{F} \\
\hline \mathrm{F} & \mathrm{F} & \mathrm{F} & \mathrm{F} & \mathrm{T} & \mathrm{F} \\
\hline
\end{array}
$$
$\therefore(p \wedge q) \wedge(\sim(p \vee q))$ is a contradiction.

Topic: Mathematics, Mathematical Reasoning, JEE Main
Which of the following is a correct match?
a. \( \mathrm{H}_{2} \mathrm{O}>\mathrm{H}_{2} \mathrm{~S}>\mathrm{H}_{2} \mathrm{Se}>\mathrm{H}_{2} \) Te : Thermal stability
b. \( \mathrm{He} < \mathrm{Ne} < \mathrm{Ar} < \mathrm{Kr} < \mathrm{Xe}: \) Ease of liquefaction
c. \( \mathrm{HF}>\mathrm{HI}>\mathrm{HBr}>\mathrm{HCl}: \) Order of boiling point
d. \( \mathrm{H}_{2} \mathrm{O} < \mathrm{H}_{2} \mathrm{~S} < \mathrm{H}_{2} \mathrm{Se} < \mathrm{H}_{2} \) Te : Reducing character

Options:
A \( a, b \) and \( d \)
B \( a, b \) and \( c \)
C Both \( a \) and \( b \)
D \( \mathrm{a}, \mathrm{b}, \mathrm{c} \) and \( \mathrm{d} \)

The correct answer is:
\( \mathrm{a}, \mathrm{b}, \mathrm{c} \) and \( \mathrm{d} \)

Solution:
The thermal stability of the hydrides of group 16 elements decreases down the group due to a decrease in M-H bond dissociation energy with an increase in the size of the central atom.

More the atomic size, more the inter molecular forces (Van der Waals forces). So, less is the ease of liquefaction.

The boiling point order: HF>HI>HBr>HCl.
HF is hydrogen bonded, thus has the highest boiling point. The boiling point of the remaining halides depends on the Van der Waals forces. Larger the size, higher is the boiling point.

From the top to the bottom in the group, atomic size increases and the ionization enthalpy decreases. Hence, acidic nature of hydrides increases. That means it can accept the electron easily.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following is a correct order of bond order ?

Options:
A C2<NO<He2+<O2-
B NO<C2<O2-<He2+
C He2+<O2-<NO<C2
D He2+<O2-<C2<NO

The correct answer is:
He2+<O2-<C2<NO

Solution:
Bond order of He2+→0.5
O2-→1.5
C2→2
NO→2.5

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
Which of the following is a correct statement?

Options:
A Aqueous solutions of $\mathrm{Cu}^{+}$and $\mathrm{Zn}^{2+}$ are colourless
B Aqueous solutions of $\mathrm{Cu}^{2+}$ and $\mathrm{Zn}^{2+}$ are colourless
C Aqueous solution of $\mathrm{Fe}^{3+}$ is green in colour
D Aqueous solution of $\mathrm{MnO}_4^{-}$is colourless

The correct answer is:
Aqueous solutions of $\mathrm{Cu}^{+}$and $\mathrm{Zn}^{2+}$ are colourless

Solution:
(a) $\mathrm{Cu}^{+}=[\mathrm{Ar}] 3 d^{10}$
(No unpaired electrons, so it is colourless)
$\mathrm{Zn}^{2+}=[\mathrm{Ar}] 3 d^{10}$
(No unpaired electrons, so it is colourless)
(b) $\mathrm{Cu}^{2+}=[\mathrm{Ar}] 3 d^9$
(One unpaired electron is present, so it is coloured) $\mathrm{Zn}^{2+}$ is colourless.
(c) The colour of $\mathrm{Fe}^{2+}$ is green while that of $\mathrm{Fe}^{3+}$ is blue.
(d) $\mathrm{MnO}_4^{-}$contains no unpaired electrons, however, it is coloured due to charge transfer.
Thus, only statement given in option (a) is correct.

Topic: Chemistry, d and f Block Elements, JEE Main
Which of the following is a correct statement?

Options:
A Continuity at x=a is sufficient for differentiability at x=a
B Differentiability at x=a is sufficient for continuity at x=a
C Existence of limit at x=a is sufficient for continuity at x=a
D Differentiability at x=a is necessary for existence of tangent at x=a

The correct answer is:
Differentiability at x=a is sufficient for continuity at x=a

Solution:
If fx is differentiable at x=a, then fx is also continuous at x=a
Hence, differentiability at x=a is sufficient for continuity at x=a

Topic: Mathematics, Continuity and Differentiability, JEE Main
Which of the following is a cyclic oxoacid ?

Options:
A H4P2O7
B H4P2O6
C H3P3O9
D H5P5O15

The correct answer is:
H3P3O9

Solution:
H3P3O9 is a cyclic trimetaphosphoric acid.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following is a diamagnetic complex

Options:
A CoNH363+
B NiCl42-
C CuCl42-
D FeH2O63+

The correct answer is:
CoNH363+

Solution:
Among the given option (a) is a diamagnetic complex.

(a) CoNH363+⇒Co27⇒Co3+=3d64s0.

Thus, has no unpaired electrons and is a diamagnetic complex.

(b) NiCl42-⇒Ni28⇒Ni2+=3d84s0

Thus, has two unpaired electrons is paramagnetic.

(c) CuCl42-⇒Cu29⇒Cu2+=3d94s0

Thus, has one unpaired electrons and is paramagnetic.

(d) FeH2O63+⇒Fe26⇒Fe3+=3d54s0

Thus, has five unpaired electrons and is paramagnetic.

Topic: Chemistry, Coordination Compounds, JEE Main
Which of the following is a FALSE statement?

Options:
A Carius tube is used in the estimation of sulphur in an organic compound.
B Phosphoric acid produced on oxidation of phosphorus present in an organic compound is precipitated as Mg2P2O7 by adding magnesia mixture.
C Carius method is used for the estimation of nitrogen in an organic compound.
D Kjeldahl's method is used for the estimation of nitrogen in an organic compound.

The correct answer is:
Carius method is used for the estimation of nitrogen in an organic compound.

Solution:
Carius method is used in the estimation of halogen in organic compounds.

Carius method involves the conversion of the halogen present in the organic compound into the corresponding silver halide. From the mass of the organic compound taken and the mass of silver halide formed, the percentage of halogen in the compound can be calculated.
Sulphur present in any organic compound is also estimated by Carius method.

Topic: Chemistry, General Organic Chemistry, JEE Main, JEE Main 2021 (26 Feb Shift 1)
Which of the following is a feature of genetic equilibrium?

Options:
A The gene pool remains constant
B Alleles frequency of a population is stable
C The total sum of all the allele frequency is 1 .
D All of the above

The correct answer is:
All of the above

Solution:
The Hardy-Weinberg equilibrium is a principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors. When mating is random in a large population with no disruptive circumstances, the law predicts that both genotype and allele frequencies will remain constant because they are in equilibrium.

Topic: Biology, Evolution, NEET
Which of the following is a feature of genetic equilibrium?

Options:
A The gene pool remains constant
B Alleles frequency of a population is stable
C The total sum of all the allele frequency is A
D All of the above

The correct answer is:
All of the above

Solution:
The Hardy-Weinberg equilibrium is a principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors. When mating is random in a large population with no disruptive circumstances, the law predicts that both genotype and allele frequencies will remain constant because they are in equilibrium.

Topic: Biology, Evolution, NEET
Which of the following is a first order reaction

Options:
A $\mathrm{NH}_4 \mathrm{NO}_2 \rightarrow \mathrm{N}_2+2 \mathrm{H}_2 \mathrm{O}$
B $2 \mathrm{HI} \rightarrow \mathrm{H}_2+\mathrm{I}_2$
C $2 \mathrm{NO}_2 \rightarrow 2 \mathrm{NO}+\mathrm{O}_2$
D $2 \mathrm{NO}+\mathrm{O}_2 \rightarrow 2 \mathrm{NO}_2$

The correct answer is:
$\mathrm{NH}_4 \mathrm{NO}_2 \rightarrow \mathrm{N}_2+2 \mathrm{H}_2 \mathrm{O}$

Solution:
It is a standard example of first order because in that reaction rate of reaction affected by only one concentration term.

Topic: Chemistry, Chemical Kinetics, JEE Main
Which of the following is a fourth root of $\frac{1}{2}+\frac{i \sqrt{3}}{2}$ (given $cis(K) = e^{iK})$

Options:
A $\operatorname{cis}\left(\frac{\pi}{2}\right)$
B $\operatorname{cis}\left(\frac{\pi}{12}\right)$
C $\operatorname{cis}\left(\frac{\pi}{6}\right)$
D $\operatorname{cis}\left(\frac{\pi}{3}\right)$

The correct answer is:
$\operatorname{cis}\left(\frac{\pi}{12}\right)$

Solution:
$\frac{1}{2}+i \frac{\sqrt{3}}{2}=\left(\cos \frac{\pi}{3}+i \sin \frac{\pi}{3}\right)$
Now $\begin{aligned} &\left(\frac{1}{2}+i \frac{\sqrt{3}}{2}\right)^{1 / 4}=\left(\cos \frac{\pi}{3}+i \sin \frac{\pi}{3}\right)^{1 / 4} \\ &=\left(\cos \frac{\pi}{12}+i \sin \frac{\pi}{12}\right)=\operatorname{cis}\left(\frac{\pi}{12}\right)\end{aligned}$

Topic: Mathematics, Complex Number, JEE Main
Which of the following is a function whose graph is symmetrical about the origin?

Options:
A fx=2x+2-x
B fx=log⁡x+1+x22
C fx+y=fx+fy∀x,y∈R
D None of these

The correct answer is:
fx+y=fx+fy∀x,y∈R

Solution:
A function whose graph is symmetrical about the origin must be odd.
2x+2-x is an even function.
Since, logâ¡x+1+x2 is an odd function,
â´logâ¡x+1+x22 is an even function.
If fx+y=fx+fyâx,yâR, then
Put x=y=0âf0=0
Now, put y=-xâfx+f-x=0
â´fx is an odd function

Topic: Mathematics, Functions, JEE Main
Which of the following is a hard magnetic material?

Options:
A Nickel-iron alloy
B Iron-silicon alloy
C Iron
D Ferrite

The correct answer is:
Ferrite

Solution:
Ferrite is a hard magnetic material. Hard magnetic materials, also called permanent magnets, retain their magnetism even when the magnetizing force is removed. Ferrites are iron oxide-containing magnetic ceramics that can be magnetized to become permanent magnets. "Hard" ferrites have high coercivity, which makes them difficult to demagnetize, and are used to make permanent magnets for things like refrigerator magnets, loudspeakers, and small electric motors.

Topic: Physics, Magnetic Properties of Matter, JEE Main
Which of the following is a Lewis acid?

Options:
A
$\mathrm{PH}_3$

B
$\mathrm{NF}_3$

C
$\mathrm{NaH}$

D
$\mathrm{B}\left(\mathrm{CH}_3\right)_3$

The correct answer is:
$\mathrm{B}\left(\mathrm{CH}_3\right)_3$

Solution:

Topic: Chemistry, Ionic Equilibrium, JEE Main, JEE Main 2018 (15 Apr Shift 1 Online)
Which of the following is a Lewis acid?

Options:
A PH3
B NF3
C NaH
D B(CH3)3

The correct answer is:
B(CH3)3

Solution:
As boron has vacant p-orbital (electron-deficient species), it will behave like a Lewis acid.

Topic: Chemistry, Ionic Equilibrium, JEE Main, JEE Main 2018 (15 Apr)
Which of the following is a major product when propylene glycol reacts with dilute nitric acid $\left(\mathrm{HNO}_3\right)$ ?

Options:
A Acetone
B Propanoic acid
C Lactic acid
D Oxalic acid

The correct answer is:
Oxalic acid

Solution:
Oxalic acid
Explanation: Oxidation of propylene glycol with dilute nitric acid can lead to the formation of oxalic acid among other products.

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which of the following is a metalloid?

Options:
A Sc
B Pb
C Bi
D Te

The correct answer is:
Te

Solution:
The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium.

Hence. tellurium is a metalloid.

All other options are metals.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2022 (26 Jun Shift 2)
Which of the following is a mismatch?

Options:
A Air (Prevention and Control of Pollution) Act - 1984
B Concept of Joint Forest movement - Introduced by government in 1980
C Ramesh Chandra Dagar - Worked on Integrated organic farming
D Water (Prevention and Control of Pollution) Act - 1986

The correct answer is:
Water (Prevention and Control of Pollution) Act - 1986

Solution:
Realising the importance of maintaining the cleanliness of the water bodies, the Government of India has passed the Water (Prevention and Control of Pollution) Act, 1974 to safeguard our water resources.

Topic: Biology, Environmental Issues, NEET
Which of the following is a negatively charged bidentate ligand?

Options:
A Cyano
B Ethylene diamine
C Acetato
D Dimethyl glyoximato

The correct answer is:
Dimethyl glyoximato

Solution:
Bidentate ligands have two coordinating sites. The structure of the given ligands are as
en and dmg both are bidentate ligands but only dmg is negatively charged, so it is the correct answer.

Topic: Chemistry, Coordination Compounds, JEE Main
Which of the following is a non-metal

Options:
A Gallium
B Indium
C Boron
D Aluminium

The correct answer is:
Boron

Solution:
The Illrd group contains boron, aluminium, gallium, indium and thallium.In these boron is the non-metallic element of the group.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main