datavorous/entrance-exam-dataset huggingface dataset:
The correct order of electron gain enthalpy is:

Options:
A S>O>Se>Te
B O>S>Se>Te
C S>Se>Te>O
D Te>Se>S>O

The correct answer is:
S>Se>Te>O

Solution:
Electron gain enthalpy is the amount of energy released when an element accepts an electron. The process is endothermic.

correct order of electron gain enthalpy is O<S>Se>Te

⇒ S>Se>Te>O

(Oxygen shows least electron gain enthalpy due to small size of atom)

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2021 (26 Feb Shift 2)
The correct order of electronegativity for given elements is

Options:
A P>Br>C>At
B Br>P>At>C
C Br>C>At>P
D C>P>At>Br

The correct answer is:
Br>C>At>P

Solution:
On the periodic table, electronegativity generally increases as you move from left to right across a period and decreases as you move down a group. As a result, the most electronegative elements are found on the top right of the periodic table, while the least electronegative elements are found on the bottom left.

Element Electronegativity

P 2.1

C 2.5

Br 3.0

At 2.2

Hence, the correct order is Br > C > At > P.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2023 (08 Apr Shift 1)
The correct order of energy of absorption for the following metal complexes is

A:Nien32+,B:NiNH362+,C:NiH2O62+

Options:
A C<B<A
B B<C<A
C C<A<B
D A<C<B

The correct answer is:
C<B<A

Solution:
Stronger the ligand, larger the splitting energy & higher the energy of absorption. Among the given options en is the strongest ligand due to ring formation than ammonia and than water. In all complex metal ion is same with same oxidation state.

Nien3+2A>NiNH36+2B>NiH2O6+2C

Topic: Chemistry, Coordination Compounds, JEE Main, JEE Main 2022 (25 Jul Shift 2)
The CORRECT order of first ionisation enthalpy is:

Options:
A Mg<S<Al<P
B Mg<Al<S<P
C Al<Mg<S<P
D Mg<Al<P<S

The correct answer is:
Al<Mg<S<P

Solution:
The ionization energy of the elements increases from left to right in the periodic table. The first ionization of magnesium is greater than that of aluminium because magnesium has a stable complete electronic configuration 1s22s22p63s2, so it requires more energy to remove the first electron from it, whereas aluminium has electronic configuration 1s22s22p63s23p1 which need lesser energy than that of magnesium. Similarly, phosphorus has more ionisation energy than sulphur due to the half filled electronic configuration in the phosphorus.

Mg Al P S→IE .order ⇒Al<Mg<S<P

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2021 (27 Jul Shift 2)
The correct order of following 3d metal oxides, according to their oxidation numbers is :

(a) CrO3

(b) Fe2O3

(c) MnO2

(d) V2O5

(e) Cu2O

Options:
A (d)>(a)>(b)>(c)>(e)
B (a)>(c)>(d)>(b)>(e)
C (a)>(d)>(c)>(b)>(e)
D (c)>(a)>(d)>(e)>(b)

The correct answer is:
(a)>(d)>(c)>(b)>(e)

Solution:
(a) Cr+6O3

(b) Fe+32O3

(c) Mn+4O2

(d) V+52O5

(e) Cu+12O

So order of oxidation state

a>d>c>b>e

Topic: Chemistry, d and f Block Elements, JEE Main, JEE Main 2021 (25 Jul Shift 1)
The correct order of heat and combustion for the following alkadienes is

Options:
A (ii) < (iii) < (i)
B (i) < (ii) < (ii)
C (iii) < (ii) < (i)
D (i) < (iii) < (ii)

The correct answer is:
(i) < (ii) < (ii)

Solution:
ΔH comb.  ∝  1 Stability of alkadiene
Stability â (i) > (ii) > (iii)
ÎHcomb.â (i) < (ii) < (iii)

Topic: Chemistry, General Organic Chemistry, JEE Main
The correct order of heat of combustion for following alkadienes is

(i)
(ii)
(iii)

Options:
A (i) < (ii) < (iii)
B (ii) < (iii) < (i)
C (i) < (iii) < (ii)
D (iii) < (ii) < (i)

The correct answer is:
(i) < (ii) < (iii)

Solution:
In lsomers of Hydrocarbon heat of combustion depends upon their stability. As stability increases, heat of combustion decreases.
trans-alkenes are more stable than cis-alkenes
Stability â1Heat of combustion
Stability a>b>c
Heat of combustion c>b>a

Topic: Chemistry, Hydrocarbons, JEE Main
The correct order of hybridisations of central atom in $\mathrm{NH}_3 \cdot\left[\mathrm{PtCl}_4\right]^{2-}, \mathrm{PCl}_5$ and $\mathrm{BCl}_3$

Options:
A $d s p^2, d s p^3, s p^2$ and $s p^3$
B $s p^3, s p^3, s p^3 d$ and $s p^2$
C $d s p^2, s p^2, s p^3$ and $d s p^3$
D $d s p^2, s p^3, s p^2$ and $d s p^3$

The correct answer is:
$s p^3, s p^3, s p^3 d$ and $s p^2$

Solution:
As we know,
Magnetic moment \(=\sqrt{n(n+2)}=2.84\)
so \(n=2\)
\(d^4\) (in strong ligand field) has two unpaired electron in octahedral field.
Hence, option (a) is correct.
All others doesnt have two unpaired electrons.

Topic: Chemistry, Coordination Compounds, JEE Main
The correct order of hydration enthalpies is

(A) K+
(B) Rb+
(C) Mg2+
(D) Cs+
(E) Ca2+

Choose the correct answer from the options given below:

Options:
A C > A > E > B > D
B E > C > A > B > D
C C > E > A > D > B
D C > E > A > B > D

The correct answer is:
C > E > A > B > D

Solution:
The hydration enthalpy of alkali metal ions decreases with an increase in ionic sizes.

So, the order is: Li+ > Na+ > K+ > Rb+ > Cs+

Like alkali metal ions, the hydration enthalpies of alkaline earth metal ions decrease with an increase in ionic size down the group.

So, the order is: Be2+ > Mg2+ > Ca2+ > Sr2+ > Ba2+

The hydration enthalpies of alkaline earth metal ions are larger than those of alkali metal ions.

So, the correct order is: Mg2+ > Ca2+ > K+ > Rb+ > Cs+

Topic: Chemistry, s Block Elements, JEE Main, JEE Main 2023 (29 Jan Shift 1)
The correct order of hydration enthalpies of alkali metal ions is:

Options:
A Na+>Li+>K+>Rb+>Cs+
B Na+>Li+>K+>Cs+>Rb+
C Li+>Na+>K+>Rb+>Cs+
D Li+>Na+>K+>Cs+>Rb+

The correct answer is:
Li+>Na+>K+>Rb+>Cs+

Solution:
Hydration Enthalpy ∝+q. (-q )
∝1r++1r-
As radius increases enthalpy of hydration decreases so in a group on going from top to bottom hydration enthalpy decreases.
Li+> Na+> K+> Rb+> Cs+

Topic: Chemistry, s Block Elements, JEE Main, JEE Main 2019 (08 Apr Shift 1)
The correct order of increasing acid strength of the compounds is
(a) $\mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H}$
(b) $\mathrm{MeOCH}_2 \mathrm{CO}_2 \mathrm{H}$
(c) $\mathrm{CF}_3 \mathrm{CO}_2 \mathrm{H}$
(d)

Options:
A
b $ < $ d $ < $ a $ < $ c
B
d $ < $ a $ < $ c $ < $ b
C
d $ < $ a $ < $ b $ < $ c
D
a $ < $ d $ < $ c $ < $ b

The correct answer is:
d $ < $ a $ < $ b $ < $ c

Solution:
No Solution Available

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main, JEE Main 2006
The correct order of increasing basic nature for the bases $\mathrm{NH}_3, \mathrm{CH}_3 \mathrm{NH}_2$ and $\left(\mathrm{CH}_3\right)_2 \mathrm{NH}$ is

Options:
A
$\left(\mathrm{CH}_3\right)_2 \mathrm{NH} < \mathrm{NH}_3 < \mathrm{CH}_3 \mathrm{NH}_2$
B
$\mathrm{NH}_3 < \mathrm{CH}_3 \mathrm{NH}_2 < \left(\mathrm{CH}_3\right)_2 \mathrm{NH}$
C
$\mathrm{CH}_3 \mathrm{NH}_2 < \left(\mathrm{CH}_3\right)_2 \mathrm{NH} < \mathrm{NH}_3$
D
$\mathrm{CH}_3 \mathrm{NH}_2 < \mathrm{NH}_3 < \left(\mathrm{CH}_3\right)_2 \mathrm{NH}$

The correct answer is:
$\mathrm{NH}_3 < \mathrm{CH}_3 \mathrm{NH}_2 < \left(\mathrm{CH}_3\right)_2 \mathrm{NH}$

Solution:
More is the no . of $+\mathrm{I}$ groups attached to $\mathrm{N}$ atom greater is the basic character.

Topic: Chemistry, Amines, JEE Main
The correct order of increasing basic nature for the bases $\mathrm{NH}_3, \mathrm{CH}_3 \mathrm{NH}_2$ and $\left(\mathrm{CH}_3\right)_2 \mathrm{NH}$ is

Options:
A
$\left(\mathrm{CH}_3\right)_2 \mathrm{NH} < \mathrm{NH}_3 < \mathrm{CH}_3 \mathrm{NH}_2$
B
$\mathrm{NH}_3 < \mathrm{CH}_3 \mathrm{NH}_2 < \left(\mathrm{CH}_3\right)_2 \mathrm{NH}$
C
$\mathrm{CH}_3 \mathrm{NH}_2 < \left(\mathrm{CH}_3\right)_2 \mathrm{NH} < \mathrm{NH}_3$
D
$\mathrm{CH}_3 \mathrm{NH}_2 < \mathrm{NH}_3 < \left(\mathrm{CH}_3\right)_2 \mathrm{NH}$

The correct answer is:
$\mathrm{NH}_3 < \mathrm{CH}_3 \mathrm{NH}_2 < \left(\mathrm{CH}_3\right)_2 \mathrm{NH}$

Solution:
More is the no . of $+\mathrm{I}$ groups attached to $\mathrm{N}$ atom greater is the basic character.

Topic: Chemistry, Amines, JEE Main, JEE Main 2003
The correct order of increasing basicity of the given conjugate bases $\left(\mathrm{R}=\mathrm{CH}_3\right)$ is

Options:
A
$\mathrm{RCO} \overline{\mathrm{O}} < \mathrm{HC}=\overline{\mathrm{C}} < \overline{\mathrm{R}} < \overline{\mathrm{N}} \mathrm{H}_2$
B
$\overline{\mathrm{R}} < \mathrm{HC} \equiv \overline{\mathrm{C}} < \mathrm{RCO} \overline{\mathrm{O}} < \overline{\mathrm{N}} \mathrm{H}_2$
C
$\mathrm{RCO} \overline{\mathrm{O}} < \overline{\mathrm{N}} \mathrm{H}_2 < \mathrm{HC} \equiv \overline{\mathrm{C}} < \overline{\mathrm{R}}$
D
$\mathrm{RCO} \overline{\mathrm{O}} < \mathrm{HC} \equiv \overline{\mathrm{C}} < \overline{\mathrm{N}} \mathrm{H}_2 < \overline{\mathrm{R}}$

The correct answer is:
$\mathrm{RCO} \overline{\mathrm{O}} < \mathrm{HC} \equiv \overline{\mathrm{C}} < \overline{\mathrm{N}} \mathrm{H}_2 < \overline{\mathrm{R}}$

Solution:
Correct order of increasing basic strength is
$$
\mathrm{R}-\mathrm{COO}^{(-)} < \mathrm{CH} \equiv \mathrm{C}^{(-)} < \mathrm{NH}_2^{(-)} < \mathrm{R}^{(-)}
$$

Topic: Chemistry, General Organic Chemistry, JEE Main, JEE Main 2010
The correct order of increasing bond angles in the following triatomic species is

Options:
A $\mathrm{NO}_2{ }^{+} < \mathrm{NO}_2^{-} < \mathrm{NO}_2$
B $\mathrm{NO}_2- < \mathrm{NO}_2{ }^{+} < \mathrm{NO}_2$
C $\mathrm{NO}_2^{-} < \mathrm{NO}_2 < \mathrm{NO}_2^{+}$
D $\mathrm{NO}_2^{+} < \mathrm{NO}_2 < \mathrm{NO}_2^{-}$

The correct answer is:
$\mathrm{NO}_2^{-} < \mathrm{NO}_2 < \mathrm{NO}_2^{+}$

Solution:
No Solution Available

Topic: Chemistry, Chemical Bonding and Molecular Structure, NEET, NEET 2008 (Mains)
The correct order of increasing energy of atomic orbitals is

Options:
A $5 p \lt 4$ f $ \lt 6$ s $ \lt 5 d$
B $5 p \lt 6 s \lt 4$ f $ \lt 5$ d
C 4 f $ \lt 5 p \lt 5 d \lt 6 s$
D $5 p \lt 5 d \lt 4 f \lt 6$ s

The correct answer is:
$5 p \lt 6 s \lt 4$ f $ \lt 5$ d

Solution:
According to Aufbau principle electron are filled in various atomic orbital in the increasing order of energy $1 s \lt 2 s \lt 2 p \lt 3 s \lt 3 p \lt 4 s \lt 3 d \lt 4 p \lt 5 s \lt 4 d \lt 5 p \lt 6 s \lt 4 f \lt 5 d \lt 6 p \lt 7 s$.

Topic: Chemistry, Structure of Atom, JEE Main
The correct order of increasing hydration energy of the following conjugate bases of oxoacids of bromine is

Options:
A BrO4-<BrO3-<BrO2-<BrO-
B BrO4-<BrO3-<BrO-<BrO2-
C BrO3-<BrO4-<BrO2-<BrO-
D BrO-<BrO2-<BrO3-<BrO4-

The correct answer is:
BrO4-<BrO3-<BrO2-<BrO-

Solution:
Hydration energy ∝ charge
Hydration energy ∝  1 size of ion

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
The correct order of increasing intermolecular hydrogen bond strength is

Options:
A HCN<H2O<NH3
B HCN<CH4<NH3
C CH4<HCN<NH3
D CH4<NH3<HCN

The correct answer is:
CH4<HCN<NH3

Solution:
The strength of Inter molecular Hydrogen bond decreases in the following order

Order of H-Bonding: CH4 < HCN < NH3

For stronger hydrogen bond the size of electronegative atoms should be small. The smaller the size of electronegative atoms, the greater is the attraction for the bonded electron pair. This causes greater polarity in the H and the electronegative atom, resulting in stronger intermolecular hydrogen bonding.

NCH . . . NCH

H2NH . . . NH3

Methane doesn't form hydrogen bonds and H2O much stronger hydrogen bonds than NH3.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main, JEE Main 2022 (27 Jun Shift 2)
The correct order of increasing s-character (in percentage) in the hybrid orbitals of following molecules/ions is
I. CO32- II. XeF4 III. I3- IV. NCl3 V.BeCl2

Options:
A II < III < IV < I < V
B II < IV < III < V < I
C III < II < I < V < IV
D II < IV < III < I < V

The correct answer is:
II < III < IV < I < V

Solution:

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main
The correct order of increasing solubility in water is

Options:
A KF<NaF<LiF
B NaHCO3<KHCO3<RbHCO3
C K2CO3<Na2CO3<Li2CO3
D LiNO3<NaNO3<KNO3

The correct answer is:
NaHCO3<KHCO3<RbHCO3

Solution:
Here the solubility order given in option B is correct
NaHCO3<KHCO3<RbHCO3
Rest orders are incorrect and the correct order of solubility in water as follows
LiF<NaF<KF
LiNO3>NaNO3>KNO3
Li2CO3<Na2CO3<K2CO3

Topic: Chemistry, s Block Elements, JEE Main
The correct order of intensity of colors of the compounds is:

Options:
A Ni(CN)42->NiCl42->NiH2O62+
B NiH2O62+>NiCl42->Ni(CN)42-
C NiCl42->NiH2O62+>Ni(CN)42-
D NiCl42->Ni(CN)42->NiH2O62+

The correct answer is:
NiCl42->NiH2O62+>Ni(CN)42-

Solution:
NiCl42->NiH2O62+>Ni(CN)42-

Splitting energy order Δt<Δ0 <Δsq

Absorbed energy order NiCl42-<NiH2O62+<Ni(CN)42-

intensity of colour of compound NiCl42->NiH2O62+>Ni(CN)42-

Topic: Chemistry, Coordination Compounds, JEE Main, JEE Main 2021 (20 Jul Shift 1)
The correct order of intensity of colors of the compounds is:

Options:
A \( \left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-}>\left[\mathrm{NiCl}_{4}\right]^{2-}>\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+} \)
B \( \left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}>\left[\mathrm{NiCl}_{4}\right]^{2-}>\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-} \)
C \( \left[\mathrm{NiCl}_{4}\right]^{2-}>\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}>\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-} \)
D \( \left[\mathrm{NiCl}_{4}\right]^{2-}>\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-}>\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+} \)

The correct answer is:
\( \left[\mathrm{NiCl}_{4}\right]^{2-}>\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}>\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-} \)

Solution:
NiCl42->NiH2O62+>Ni(CN)42-

Splitting energy order Δt<Δ0 <Δsq

Absorbed energy order NiCl42-<NiH2O62+<Ni(CN)42-

intensity of colour of compound NiCl42->NiH2O62+>Ni(CN)42-

Topic: Chemistry, Coordination Compounds, JEE Main
The correct order of ionic radii for the ions, P3-, S2-, Ca2+, K+, Cl- is :

Options:
A P3->S2->Cl->K+>Ca2+
B P3->S2->Cl->Ca2+>K+
C Cl->S2->P3->Ca2+>K+
D K+>Ca2+>P3->S2->Cl-

The correct answer is:
P3->S2->Cl->K+>Ca2+

Solution:
P3-S2-C-K+Ca2+Z1516171920No.of e-1818181818

For isoelectronic species greater is Z smaller is radius. So correct order

P3->S2->Cl->K+>Ca2+

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2021 (27 Aug Shift 2)
The correct order of ionic size of N3-,Na+,F-,Mg2+ and O2- is :

Options:
A Mg2+<Na+<F-<O2-<N3-
B N3-<O2-<F<Na+<Mg2+
C F-<Na+<O2-<Mg2+<N3-
D Na+<F-<Mg2+<O2-<N3-

The correct answer is:
Mg2+<Na+<F-<O2-<N3-

Solution:
These are all isoelectronic species. More the negative charge on the species, more is the size of that ion and more the positive charge on the species, less is the size of that ion.

The correct order of ionic radii isN-3>O-2>F->Na+>Mg+2Radii

(Isoelectronic species)

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2022 (27 Jun Shift 2)
The correct order of ligands in the spectrochemical series is

Options:
A
$\mathrm{Cl}^{-}>$en $>\mathrm{CN}^{-}>\mathrm{NCS}^{-}$

B
$\mathrm{CN}^{-}>$en $>\mathrm{NCS}^{-}>\mathrm{Cl}^{-}$

C
$\mathrm{NCS}^{-}>\mathrm{CN}^{-}>\mathrm{Cl}^{-}>$en

D
en $>\mathrm{CN}^{-}>\mathrm{Cl}^{-}>\mathrm{NCS}^{-}$

The correct answer is:
$\mathrm{CN}^{-}>$en $>\mathrm{NCS}^{-}>\mathrm{Cl}^{-}$

Solution:
Correct order is : $\mathrm{CN}^{-}>$en $>\mathrm{NCS}^{-}>\mathrm{Cl}^{-}$

Topic: Chemistry, Coordination Compounds, JEE Main
The correct order of ligands in the spectrochemical series is

Options:
A
$\mathrm{Cl}^{-}>$en $>\mathrm{CN}^{-}>\mathrm{NCS}^{-}$

B
$\mathrm{CN}^{-}>$en $>\mathrm{NCS}^{-}>\mathrm{Cl}^{-}$

C
$\mathrm{NCS}^{-}>\mathrm{CN}^{-}>\mathrm{Cl}^{-}>$en

D
en $>\mathrm{CN}^{-}>\mathrm{Cl}^{-}>\mathrm{NCS}^{-}$

The correct answer is:
$\mathrm{CN}^{-}>$en $>\mathrm{NCS}^{-}>\mathrm{Cl}^{-}$

Solution:
Correct order is : $\mathrm{CN}^{-}>$en $>\mathrm{NCS}^{-}>\mathrm{Cl}^{-}$

Topic: Chemistry, Coordination Compounds, JEE Main, JEE Main 2012 (19 May Online)
The correct order of magnetic moments (spin only values in B.M.) among is

Options:
A
$\left[\mathrm{MnCl}_4\right]^{2-}>\left[\mathrm{CoCl}_4\right]^{-2}>\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{-4}$

B
$\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{-4}>\left[\mathrm{CoCl}_4\right]^{2-}>\left[\mathrm{MnCl}_4\right]^{2-}$

C
$\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}>\left[\mathrm{MnCl}_4\right]^{2-}>\left[\mathrm{CoCl}_4\right]^{2-}$

D
$\left[\mathrm{MnCl}_4\right]^{2^{-}}>\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}>\left[\mathrm{CoCl}_4\right]^{2-}$
(Atomic numbers: $\mathrm{Mn}=25 ; \mathrm{Fe}=26, \mathrm{Co}=27$ )

The correct answer is:
$\left[\mathrm{MnCl}_4\right]^{2-}>\left[\mathrm{CoCl}_4\right]^{-2}>\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{-4}$

Solution:
No Solution Available

Topic: Chemistry, Coordination Compounds, JEE Main, JEE Main 2004
The correct order of melting point is

Options:
A Sr>Ca>Mg>Be
B Be>Mg>Ca>Sr
C Be>Ca>Sr>Mg
D Be>Ca>Mg>Sr

The correct answer is:
Be>Ca>Sr>Mg

Solution:
Alkali metal	Melting point

Mg	924 K

Sr	1062 K

Ca	1124 K

Be	1560 K

Topic: Chemistry, s Block Elements, JEE Main, JEE Main 2022 (26 Jun Shift 1)
The correct order of melting point of dichlorobenzenes is

Options:
A
B
C
D

The correct answer is:

Solution:
Out of the three isomers of dichlorobenzene, the para-isomer is more symmetrical than the other two isomers, So, it has a more closely packed arrangement of molecules in its crystal lattice. So, para-dichlorobenzene has a higher melting point as compared to ortho and meta Isomers.

Melting point of ortho-dichlorobenzene, meta-dichlorobenzene and para-dichlorobenzene are 256K, 249K, 323K respectively.

Bromo, iodo and polychloro derivatives of hydrocarbons are heavier than water. The density increases with increase in number of carbon atoms, halogen atoms and atomic mass of the halogen atoms.

So, the correct option is D.

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main, JEE Main 2023 (31 Jan Shift 1)
The correct order of melting points of hydrides of group 16 elements is

Options:
A H2S<H2Se<H2Te<H2O
B H2O<H2S<H2Se<H2Te
C H2S<H2Te<H2Se<H2O
D H2Se<H2S<H2Te<H2O

The correct answer is:
H2S<H2Se<H2Te<H2O

Solution:
In general molar mass ↑,MP↑ but in H2O due to H-bonding, it is maximum among the following:

Property	H2O	H2S	H2Se	H2Te

m.p./K	273	188	208	222

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main, JEE Main 2022 (26 Jun Shift 1)
The correct order of metallic character is

Options:
A K > Be > Ca
B Be > Ca > K
C Ca > K > Be
D K > Ca > Be

The correct answer is:
K > Ca > Be

Solution:
The metallic character of an element is defined as the easiness of its atom in losing electrons. According to the modern periodic table, the metallic character of an element decreases while moving from left to right across a period. K is an alkali metal. For alkaline earth metals, metallic character increases down the group. Hence, the correct order of metallic character is K>Ca>Be.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2023 (10 Apr Shift 2)
The correct order of molar conductivity at infinite dilution of LiCl, NaCl and KCl is

Options:
A LiCl>KCl> NaCl
B KCl>NaCl>LiCl
C LiCl>NaCl>KCl
D NaCl>KCl>LiCl

The correct answer is:
KCl>NaCl>LiCl

Solution:
Ionic mobility depends upon the charge to size ratio of ion. The ionic size in case of hydrated cation is
K+aq<Na+aq< Li+aq
size of cation is less, will attracted by more H 2 O molecules so becomes more bulky hence, does not move easily.

Topic: Chemistry, Electrochemistry, JEE Main
The correct order of nucleophilicity is

Options:
A F->OH-
B H2O¨>OH-
C ROH>RO-
D NH2->NH3

The correct answer is:
NH2->NH3

Solution:
Nucleophilicity is directly proportional to the electro density on donor atom and the size of donor atom (in gas)

And Stronger the base, greater the nucleophilicity.

As weak acid will have a strong conjugate base NH2- is stronger base than ammonia.Hence, NH2- is a stronger nucleophile than ammonia

Topic: Chemistry, General Organic Chemistry, JEE Main, JEE Main 2022 (26 Jun Shift 2)
The correct order of pKa values for the following compounds is:

Options:
A c > a > d > b
B b > d > a > c
C b > a > d > c
D a > b > c > d

The correct answer is:
b > d > a > c

Solution:
Electron-withdrawing groups increase the acidic nature of the phenol. Nitro group is electron withdrawing group, hence it is the more acidic compound among the given phenols.

Electron-donating groups decrease the acidic nature where methoxy group is more electron donating, hence less acidic than the iso-propyl group which donates electrons by hyperconjugation effect.

∴ Order of acidic strength is (c) > (a) > (d) > (b)

The order of pKa values are (b) > (d) >(a) > (c).

Topic: Chemistry, General Organic Chemistry, JEE Main, JEE Main 2023 (30 Jan Shift 2)
The correct order of reactivity for the addition reaction of the following carbonyl compounds with ethyl magnesium iodide is

Options:
A I > III > II > IV
B IV > III > II > I
C I > II > IV > III
D III > II > I > IV

The correct answer is:
I > III > II > IV

Solution:
If the carbony carbon is stericaly crowded then it will be reluctant to undergo addition reaction. Moreover, attachment of bulkier alkyl groups with the carbonyl carbon lessens its positive charge resulting into the minimisation of attack by from RMgBr.

Topic: Chemistry, Aldehydes and Ketones, JEE Main
The correct order of reactivity of following haloarenes towards nucleophilic substitution with aqueous NaOH is:

Choose the correct answer from the options given below:

Options:
A A >B>D>C
B C>A>D>B
C D>C>B>A
D D>B>A>C

The correct answer is:
D>B>A>C

Solution:
The intermediate formed in aromatic nucleophilic substitution reaction is carbanion. Carbanion stabilised by electron withdrawing groups. Aryl halides are less reactive towards nucleophilic aromatic substitution with aqueous NaOH. Introduction of electron releasing group like OCH3 group further decreases its reactivity towards nucleophilic substitution. But the introduction of electron withdrawing groups like NO2 group particularly at the ortho and para position increases its reactivity towards nucleophilic substitution. Higher the number of electron withdrawing groups, higher the reactivity.
∴ The correct reactivity order is

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main, JEE Main 2023 (08 Apr Shift 2)
The correct order of reactivity of $P h M g B r$ with

Options:
A (I) > (II) > (III)
B (III) $\gt$ (II) $\gt$ (I)
C $(\mathrm{II})\gt(\mathrm{III})\gt(\mathrm{I})$
D $(\mathrm{I})\gt(\mathrm{III})\gt(\mathrm{II})$

The correct answer is:
$(\mathrm{II})\gt(\mathrm{III})\gt(\mathrm{I})$

Solution:
In nucleophilic addition reaction, the carbonyl compound will respond in preference which is sterically more exposed and electronically have intact positive charge over carbonyl carbon. So reactivity order towards reaction with $p h \mathrm{MgBr}$ is $(\mathrm{II})\gt($ III) $\gt(\mathrm{I})$.

Topic: Chemistry, Aldehydes and Ketones, JEE Main
The correct order of reactivity of the given chlorides with acetate in acetic acid is :

Options:
A
B
C
D

The correct answer is:

Solution:
The given compounds in Acetate in Acetic acid solution reacts through SN1 mechanism. The stability of carbocation is directly proportion to reactivity via SN1 mechanism.

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main, JEE Main 2021 (31 Aug Shift 1)
The correct order of reduction potentials of the following pairs is

A. Cl2/Cl-

B. I2/I-

C. Ag+/Ag

D. Na+/Na

E. Li+/Li

Choose the correct answer from the options given below.

Options:
A A>B>C>E>D
B A>C>B>E>D
C A>B>C>D>E
D A>C>B>D>E

The correct answer is:
A>C>B>D>E

Solution:
ECl2∣Cl−0=1.36E∘I2∣I−=0.54ELi+|Li=−3.05E∘Ag+∣Ag=0.80ENa+|Na=−2.71

So, we can clearly see the order of reduction potential.

A>C>B>D>E

Topic: Chemistry, Electrochemistry, JEE Main, JEE Main 2022 (25 Jun Shift 2)