datavorous/entrance-exam-dataset huggingface dataset:
Which of the following options explains how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?

Options:
A because the effective nuclear charge experienced by outer electrons increases.
B because electrons are added to the same principal energy level.
C because the atomic radius of the elements increases.
D because 3d orbitals acquire only one electron in each of the five 3d orbitals [i.e., each d-orbital remains half-filleD] and inter electronic repulsion is the least and nuclear charge increases.

The correct answer is:
because 3d orbitals acquire only one electron in each of the five 3d orbitals [i.e., each d-orbital remains half-filleD] and inter electronic repulsion is the least and nuclear charge increases.

Solution:
Correct Option is : (D)
because 3d orbitals acquire only one electron in each of the five 3d orbitals [i.e., each d-orbital remains half-filleD] and inter electronic repulsion is the least and nuclear charge increases.

Topic: Chemistry, d and f Block Elements, NEET
Which of the following options gives the correct match w.r.t. the disease, its causative organism and mode of infection?

Options:
A

Disease	Causative Organism	Mode of infection

Pneumonia	Haemophilus influenzae	Vector borne

B

Disease	Causative Organism	Mode of infection

Malaria	Plasmodium vivax	Bite of female Culex mosquito

C

Disease	Causative Organism	Mode of infection

Amoebiasis	Enatamoeba histolytica	Faeco-oral route

D

Disease	Causative Organism	Mode of infection

Ascariasis	Filarial worm	With infected food and water

The correct answer is:

Disease	Causative Organism	Mode of infection

Amoebiasis	Enatamoeba histolytica	Faeco-oral route

Solution:
Entamoeba histolytica is a protozoan parasite that causes amoebiasis. Symptoms include constipation, abdominal pain and cramps, stools with excess mucous, and blood clots. Drinking water and food contaminated by the fecal the matter is the main source of amoebiasis infection. Pneumonia is transmitted by droplet infection and not by vectors. Malaria is spread by female Anopheles mosquito. Ascariasis is caused by a round worm Ascaris lumbricoides and not filarial worm.

Topic: Biology, Human Health and Diseases, NEET
Which of the following options is true for a secretory cell?

Options:
A
Golgi apparatus is absent.

B
RER is easily observed in the cell.

C
Only SER is present

D
Secretory granules are formed in nucleus

The correct answer is:
RER is easily observed in the cell.

Solution:
Rough endoplasmic reticulum (RER) mainly consists of cisternae. Ribosomes are attached on its cytoplasmic surface. This makes the surface look rough or granular. The RER often occurs deep in the cytoplasm. It is used to synthesize and secrete proteins.

Topic: Biology, Cell - The Unit of Life
Which of the following orbitals are degenerate?

3d xy , 4d xy , 3d z 2 , 3d yz , 5d z 2

Options:
A 3d xy , 3d z 2 , 3d yz
B 4d xy , 3d z 2 , 3d yz
C 3d z 2 , 3d yz , 5d z 2
D None

The correct answer is:
3d xy , 3d z 2 , 3d yz

Solution:
The orbitals which belongs to same subshell and same shell are called degenerate orbitals. 3dxy, 3dz2, 3dyzand4dxy, 4dyz, 4dz2 are the two sets of degenerate orbitals.

Topic: Chemistry, Structure of Atom, JEE Main
Which of the following order is correct for the property mentioned in brackets?

Options:
A S2->Cl->K+>Ca2+ (Ionization energy)
B C<N<F<O (2nd Ionization energy)
C B>Al>Ga>In>Tl (Electronegativity)
D Na+>Li+>Mg3+>Be2+>Al3+ (Ionic radius)

The correct answer is:
C<N<F<O (2nd Ionization energy)

Solution:
A. Correct order →Ca2+>K+>Cl->S2- (ionization energy)
for isoelectronic species (I.E. ∝Zeff )
B. Correct order →C<N<F<O (2nd I.E.)
Second electron removal from oxygen requires more energy as it acquires stable 2s22p3 configuration after removal of one electron.
C. →B>Tl>In>Ga>Al (Electronegativity)
In general EN increases in boron family from top to bottom due to increase in Zeff on valence shell while boron has highest E.N. due to its vary small size.
D. Correct order →Na+>Li+>Mg2+>Al3+>Be2+ (Ionic radius)
Ionic radius depends on Zeff and number of shells.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main
Which of the following order is not correct?

Options:
A $\mathrm{MeBr}>\mathrm{Me}_{2} \mathrm{CHBr}>\mathrm{Me}_{3} \mathrm{CBr}>$
$\mathrm{Et}_{3} \mathrm{CBr}\left(\mathrm{S}_{\mathrm{N}} 2\right)$
B $\mathrm{Me}_{3} \mathrm{CBr}>\mathrm{Me}_{2} \mathrm{CHBr}>\mathrm{Me}_{2} \mathrm{CH.CH}_{2} \mathrm{Br}>$
$\mathrm{MeCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br} .\left(\mathrm{E}_{2}\right)$
C $\mathrm{PhCH}_{2} \mathrm{Br}>\mathrm{Ph} \mathrm{CHBrMe}>\mathrm{PhCBrMe}_{2}>$
$\operatorname{PhCBrMePh}\left(\mathrm{S}_{\mathrm{N}} 1\right)$
D $\mathrm{MeI}>\mathrm{MeBr}>\mathrm{MeCl}>\mathrm{MeF}\left(\mathrm{S}_{\mathrm{N}} 2\right)$

The correct answer is:
$\mathrm{PhCH}_{2} \mathrm{Br}>\mathrm{Ph} \mathrm{CHBrMe}>\mathrm{PhCBrMe}_{2}>$
$\operatorname{PhCBrMePh}\left(\mathrm{S}_{\mathrm{N}} 1\right)$

Solution:
The more is the stability of intermediate carbonium ion, the more is the chance of $\mathrm{S}_{\mathrm{N}} 1$ mechanism. The intermediates obtained will be
$\mathrm{Ph}^{+} \mathrm{C} \mathrm{H}_{2}(\mathrm{i}), \mathrm{Ph} \mathrm{C} \mathrm{H}-\mathrm{Me}(\mathrm{ii})$
$\mathrm{Ph} \mathrm{C}-\mathrm{Me}_{2}\left(\right.$ iii) $, \mathrm{Ph} \mathrm{C}^{+} \mathrm{MePh}$ (iv)
The stabilty is of the order iv $>\mathrm{iii}>\mathrm{ii}>\mathrm{i}$

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main
Which of the following order is true regardingthe acidic nature of phenol?

Options:
A Phenol > O-cresol > o-nitrophenol
B O-cresol < phenol < O-nitrophenol
C phenol < O-cresol > O-nitrophenol
D phenol < O-cresol < O-nitrophenol

The correct answer is:
O-cresol < phenol < O-nitrophenol

Solution:
Acidity of the substituted phenols is affected by the nature of the substituents.
Presence of \( e^{-} \)withdrawing group such as \( -\mathrm{NO}_{2} \) increases the acidic strength whereas \( e^{-} \)releasing or donating
groups at 0- and p- position decreases acidic strength of substituted phenol.
In cresol (o- or p- cresol) methyl groups shows + I effect, soit destabilizes the anion formed after ionization hence cresol
is less acidic and o-nitrophenol is more acidic than carbolic acid (phenol). Hence, the correct order for the acidic nature
is o-cresol < phenol < o-nitrophenol.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which Of the following orders is correct?
(1) SbH3>NH3>AsH3>PH3 - Boiling Point
(2) NH3>PH3>AsH3>SbH3 - Thermal Stability
(3) NH3>PH3>AsH3>SbH3 - Basic Character
(4) NH3>PH3>AsH3>SbH3 - Bond Angle

Options:
A (1), (2) and (3) only
B (2), (3) and (4) only
C (1), (3) and (4) only
D (1), (2), (3) and (4).

The correct answer is:
(1), (3) and (4) only

Solution:
(1) NH3 has higher boiling point than AsH3 and PH3 on account H ‐bonding. SbH3 has highest boiling point on account of highest molecular weight.
(2) As the size of element increases, the strength of M‐H bond decreases and thus stability decreases.
(3) Basicity decreases down the group. (Drago rule).
(4) HEH angle (∘ ) :NH3=107.8;PH3=93.6,AsH3=91.8;SbH3=91.3.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following orders is correct regarding the acidity of carboxylic group?

Options:
A \( \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Cl}) \mathrm{COOH}>\mathrm{CH}_{3} \mathrm{CH}(\mathrm{Cl}) \mathrm{CH}_{2} \mathrm{COOH}>\mathrm{ClCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOH} \)
B \( \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Cl}) \mathrm{COOH} < \mathrm{CH}_{3} \mathrm{CH}(\mathrm{Cl}) \mathrm{CH}_{2} \mathrm{COOH} < \mathrm{ClCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOH} \)
C \( \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Cl}) \mathrm{COOH}>\mathrm{CH}_{3} \mathrm{CH}(\mathrm{Cl}) \mathrm{CH}_{2} \mathrm{COOH} < \mathrm{ClCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOH} \)
D \( \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Cl}) \mathrm{COOH} < \mathrm{CH}_{3} \mathrm{CH}(\mathrm{Cl}) \mathrm{CH}_{2} \mathrm{COOH}>\mathrm{ClCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOH} \)

The correct answer is:
\( \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Cl}) \mathrm{COOH}>\mathrm{CH}_{3} \mathrm{CH}(\mathrm{Cl}) \mathrm{CH}_{2} \mathrm{COOH}>\mathrm{ClCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{COOH} \)

Solution:
1.Acidity depends on stability of carboxate ion formed 'CI' attached to ' ∝ ' - carbon has more -I effect which stabilises the carboxalate ion.

2.+I effect depend on distance.

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which of the following orders is incorrect with respect to the property indicated ?

Options:
A NH3<PH3<AsH3 (acidic behaviour)
B Li<Be<B<C (first ionisation energy)
C Al2O3<MgO<Na2O<K2O (basic character)
D Li+<Na+<K+<Cs+ (ionic radius)

The correct answer is:
Li<Be<B<C (first ionisation energy)

Solution:
(i) Bond angle of NH 3 = 107 o
PH 3  >  AsH 3 = 90 o
According to bond angle the %s character of lp in NH 3 =22% while in PH 3 & AsH 3 having approximately 100%, so the donation of lp in PH 3 & AsH 3 are difficult. Hence, the acidic character increases and the order of acidic character is NH 3 < PH 3 < AsH 3 is correct
(ii) On moving left to right in a period ionisation energy increases. Li<Be<B<C but the first ionisation potential of Be is higher than that of B because Be has fulfilled configuration.
(iii) Metallic character increases hence the basic character of oxide increases.
(iv) In a group from top to the bottom, the number of the shell increases hence radius increases.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main
Which of the following orders of relative strengths of acids is correct

Options:
A $\mathrm{FCH}_2 \mathrm{COOH}\gt\mathrm{ClCH}_2 \mathrm{COOH}\gt\mathrm{BrCH}_2 \mathrm{COOH}$
B $\mathrm{ClCH}_2 \mathrm{COOH}\gt\mathrm{Br}_2 \mathrm{CH}_2 \mathrm{COOH}\gt\mathrm{FCH}_2 \mathrm{COOH}$
C $\mathrm{BrCH}_2 \mathrm{COOH}\gt\mathrm{ClCH}_2 \mathrm{COOH}\gt\mathrm{FCH}_2 \mathrm{COOH}$
D $\mathrm{ClCH}_2 \mathrm{COOH}\gt\mathrm{FCH}_2 \mathrm{COOH}\gt\mathrm{BrCH}_2 \mathrm{COOH}$

The correct answer is:
$\mathrm{FCH}_2 \mathrm{COOH}\gt\mathrm{ClCH}_2 \mathrm{COOH}\gt\mathrm{BrCH}_2 \mathrm{COOH}$

Solution:
Acidity decreases with the decrease in electronegativity of halogen i.e.,
$\mathrm{FCH}_2 \mathrm{COOH}\gt\mathrm{ClCH}_2 \mathrm{COOH}\gt\mathrm{BrCH}_2 \mathrm{COOH}$

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which of the following orders regarding ionization energy is correct?

Options:
A $\mathrm{N}>\mathrm{O}>\mathrm{F}$
B $\mathrm{N} < \mathrm{O} < \mathrm{F}$
C $\mathrm{N}>\mathrm{O} < \mathrm{F}$
D $\mathrm{N} < \mathrm{O}>\mathrm{F}$

The correct answer is:
$\mathrm{N}>\mathrm{O} < \mathrm{F}$

Solution:
Hints : As IE $1 \mathrm{~N}>\mathrm{O}$ (because of half filled orbitals of $\mathrm{N}$ ) and $\mathrm{O} < \mathrm{F}$ (because of smaller size of $\mathrm{F}$ )

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main
Which of the following ore is concentrated using group 1 cyanide salt?

Options:
A Malachite
B Calamine
C Siderite
D Sphalerite

The correct answer is:
Sphalerite

Solution:
Sphalerite ore: ZnS

Calamine ore: ZnCO3

Siderite ore: FeCO3

Malachite ore: CuOH2·CuCO3
It is possible to separate two sulphide ores by adjusting proportion of oil to water or by using 'depressants'. In case of an ore containing ZnS and PbS, the depressant used is NaCN.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main, JEE Main 2021 (24 Feb Shift 1)
Which of the following ores is subjected to roasting during metallurgical operations for getting the metal oxide

Options:
A Horn silver
B Zinc blende
C Malachite
D Limonite

The correct answer is:
Zinc blende

Solution:
Correct Option is 2 Zinc blende
$\underset{\text{Zinc Blende}\qquad \quad}{2 \mathrm{ZnS}+3 \mathrm{O}_2+}$ heat $\rightarrow 2 \mathrm{ZnO}+2 \mathrm{SO}_2$

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main
Which of the following organ never helps in oxygenation of blood in any vertebrate, at any stage of their life?

Options:
A Skin
B Lungs
C Gills
D Kidney

The correct answer is:
Kidney

Solution:
Vertebrates such as amphibians have 3-chambered heart, muscular, myogenic heart with two atria and single ventricle. In amphibians, the left atrium receives oxygenated blood from the gills/lungs/skin and the right atrium gets the deoxygenated blood from other body parts.
In amniota group, i.e. reptiles, birds and mammals, respiration is mainly pulmonary, in fishes it is through gills.
In vertebrates, the kidney is mainly involved in osmoregulation and excretion.

Topic: Biology, Animal Kingdom, NEET
Which of the following organic compounds answers to both iodoform test and Fehling's test?

Options:
A Ethanol
B Methanal
C Ethanal
D Propanone

The correct answer is:
Ethanal

Solution:
The compound which contains âCOCH3 group in its structure, give positive iodoform test and the compound which contains âCHO group give positive Fehling test.
In ethanal, CH3CHO both the groups are present, hence it responds to both iodoform test and Fehling's test.
Iodoform test
CH3CHO+I2+NaOHâCHI3+NaI+H2O
Fehling's test
CH 3 CHO+Cu ( OH ) 2 → CH 2 COOH+ Cu 2 O↓ ( red ppt. ) +2 H 2 O

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Which of the following organic compounds could not be dried by anhydrous $\mathrm{CaCl}_{2}$ ?

Options:
A Ethanol
B Benzene
C Chloroform
D Ethyl acetate

The correct answer is:
Ethanol

Solution:
Ethanol could not be dried by anhydrous $\mathrm{CaCl}_{2}$ because it reacts with $\mathrm{CaCl}_{2}$ as follows

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Which of the following organic compounds is the main constituent of lecithin?

Options:
A Arachidonic acid
B Phospholipid
C Cholesterol
D Phosphoprotein

The correct answer is:
Phospholipid

Solution:
Phospholipids are main constituents of lecithin. These molecules are composed of choline and inositole. It is found in all living cells as a major component of cell membrane.

Topic: Biology, Biomolecules (B), NEET, NEET 2019 (Odisha)
Which of the following organism show budding?

Options:
A Yeast
B Hydra
C Sponges
D All of these

The correct answer is:
All of these

Solution:
In yeast the division is unequal and small buds are produced that remains attached initially to the parent cell which, eventually gets separated and matures into new yeast organism. In multicellular organism exogenous bud is formed by Hydra and endogenous bud is formed by sponges.

Topic: Biology, Reproduction in Organisms, NEET
Which of the following organisms follow the graphs I, II and III respectively?

Options:
A I - Salamandra, II - Trygon, III - Corvus
B I - Struthio, II - Myxine, III - Sorex
C I - Balanoglossus, II - Amphioxus, III - Canis
D I - Hippocampus, II - Psittacula, III - Spermophilus

The correct answer is:
I - Hippocampus, II - Psittacula, III - Spermophilus

Solution:
Graph I depicts conformers, Graph II depicts regulators, Graph III depicts partial regulators
Salamandra (Salamander)- an amphibian, Trygon (Sting ray) - a cartilaginous fish, Hippocampus (seahorse) - a bony fish, Myxine (hag fish) - a cyclostome, Balanoglossus - a hemichordate, Amphioxus - a cephalochordate can't regulate their body temperature. Their internal temperature changes with the surrounding, so they are Conformers. Corvus (crow), Struthio (ostrich), Psittacula (parrot) are all birds and can regulate their internal body temperature. Hence they are regulators. Canis (dog) is a mammal which is a regulator too. Spermophilus tridecemlineatus (ground squirrel) and Sorex araneus (shrews) are mammals which are partial regulators. At low temperatures their internal temperature rises with the external temperature but as the temperature increases they maintain a constant internal temperatures

Topic: Biology, Organisms and Populations, NEET
Which of the following organometallic compound is and bonded

Options:
A $\mathrm{Fe}\left(\mathrm{CH}_3\right)_3$
B $\left[\mathrm{Fe}\left(\eta^5-\mathrm{C}_5 \mathrm{H}_5\right)_2\right]$
C $\left[\mathrm{Co}(\mathrm{CO})_5 \mathrm{NH}_3\right]^{2+}$
D $K\left[P t C l_3\left(n^2-C_2 H_4\right)\right]$

The correct answer is:
$\left[\mathrm{Fe}\left(\eta^5-\mathrm{C}_5 \mathrm{H}_5\right)_2\right]$

Solution:
$\left[\mathrm{Fe}\left(\eta^5-\mathrm{C}_5 \mathrm{H}_5\right)_2\right]$ is the organometallic compound which has $\sigma$ and $\pi$ bonds present.

Topic: Chemistry, Coordination Compounds, JEE Main
Which of the following outer electronic configuration represents argon?

Options:
A $n s^2$
B $n s^2 n p^6$
C $n s^2 n p^3$
D $n s^2 n p^4$

The correct answer is:
$n s^2 n p^6$

Solution:
$n s^2 n p^6$ - Argon

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following outer octahedral complexes have same number of unpaired electrons?
1. \(\left[\mathrm{MnCl}_6\right]^{3-}\)
2. \(\left[\mathrm{FeF}_6\right]^{3-}\)
3. \(\left[\mathrm{CoF}_6\right]^{3-}\)
4. \(\left[\mathrm{Ni}\left(\mathrm{NH}_3\right)_6\right]^{2+}\)

Options:
A 1 and 3
B 1 and 2
C 3 and 4
D 2 and 3

The correct answer is:
1 and 3

Solution:
All four complexes given are outer orbital or high spin octahedral complexes. So, \(d\)-orbital electrons of central metal ions of the complexes remain unaffected by weak field ligands.
So, \(d\)-configuration of free \(M^{n+}\) and coordinated \(M^{n+}\) will remain same.
1.
1. \(\left[\mathrm{Mn} \mathrm{Cl}_6\right]^{3-} \longrightarrow \mathrm{Mn}^{3+} \Rightarrow d^4, n=4\)
[ \(\because n=\) Number of unpaired electrons]
2. \(\left[\mathrm{FeF}_6\right]^{3-} \longrightarrow \mathrm{Fe}^{3+} \Rightarrow d^5, n=5\)
3. \(\left[\mathrm{CoF}_6\right]^{3-} \longrightarrow \mathrm{Co}^{3+} \Rightarrow d^6, n=4\)
4. \(\left[\mathrm{Ni}\left(\mathrm{NH}_3\right)_6\right]^{2+} \longrightarrow \mathrm{Ni}^{2+} \Rightarrow d^3, n=2\)
So, complexes 1 and 3 have same number of unpaired electrons \((n=4)\).

Topic: Chemistry, Coordination Compounds, AP EAMCET, AP EAMCET 2020 (17 Sep Shift 2)
Which of the following oxidation states are the most characteristics for lead and tin respectively?

Options:
A $+2,+4$
B $+4,+4$
C $+2,+2$
D $+4,+2$

The correct answer is:
$+2,+4$

Solution:
The group IV elements show tetravalency due to shifting of one electrons of $n s$ to the vacant $n p$ orbital. These four orbitals give rise to four $s p^3$ hybrid orbitals. However, $\mathrm{Ge}, \mathrm{Sn}$ and $\mathrm{Pb}$, have a tendency to form divalent as well as tetravalent ions. As the inert pair effect increases from $\mathrm{Ge}$ to $\mathrm{Pb}$, the stability of tetravalent ion decreases and that of divalent ion increases. Thus, $\mathrm{Pb}^{++}$is more stable than $\mathrm{Pb}^{4+}$ and $\mathrm{Sn}^{4+}$ ions is more stable than $\mathrm{Sn}^{2+}$.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Which of the following oxidation states is the most common among the lanthanoids?

Options:
A 4
B 2
C 5
D 3

The correct answer is:
3

Solution:
The most common oxidation state exhibited by lanthanoids is +3 .

Topic: Chemistry, d and f Block Elements, NEET, NEET 2010 (Mains)
Which of the following oxide is amphoteric?

Options:
A $\mathrm{SnO}_2$
B $\mathrm{CaO}$
C $\mathrm{SiO}_2$
D $\mathrm{CO}_2$

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

Solution:
$\mathrm{SnO}_2$ is an amphoteric oxide because it reacts with acids as well as bases to form corresponding salts.
$$
\begin{aligned}
& \mathrm{SnO}_2+4 \mathrm{HCl} \longrightarrow \mathrm{SnCl}_4+2 \mathrm{H}_2 \mathrm{O} \\
& \mathrm{SnO}_2+2 \mathrm{NaOH} \longrightarrow \begin{array}{c}
\mathrm{Na}_2 \mathrm{SnO}_3+\mathrm{H}_2 \mathrm{O} \\
\text { sod. stannate }
\end{array}
\end{aligned}
$$

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET, NEET 2011 (Mains)
Which of the following oxide of nitrogen is the anhydride of $\mathrm{HNO}_3$

Options:
A $\mathrm{NO}$
B $\mathrm{N}_2 \mathrm{O}_3$
C $\mathrm{N}_3 \mathrm{O}_4$
D $\mathrm{N}_2 \mathrm{O}_3$

The correct answer is:
$\mathrm{N}_2 \mathrm{O}_3$

Solution:
\(\underset{\text{Nitric acid}}{2 \mathrm{HNO}_3} \rightarrow \mathrm{N}_2 \mathrm{O}_5+\mathrm{H}_2 \mathrm{O}\)

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following oxides are acidic ?
CuO,  Mn 2 O 7 , CO,  SO 2 ,  CrO 3

Options:
A CrO 3 ,  Mn 2 O 7 and SO 2
B Only SO 2
C Mn 2 O 7 and SO 2
D CO and SO 2

The correct answer is:
CrO 3 ,  Mn 2 O 7 and SO 2

Solution:
CuO is basic oxide and CO is neutral oxide.
CrO 3 + H 2 O â H 2 CrO 4 Acid
SO 2 + H 2 O â H 2 SO 3 acid Mn 2 O 7 + H 2 O â 2 HMnO 4 acid

Topic: Chemistry, d and f Block Elements, JEE Main
Which of the following oxides is amphoteric in character?

Options:
A
$\mathrm{CaO}$

B
$\mathrm{CO}_2$

C
$\mathrm{SiO}_2$

D
$\mathrm{SnO}_2$

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

Solution:
$\mathrm{CaO} \longrightarrow$ basic
$\mathrm{SiO}_2 \& \mathrm{CO}_2 \longrightarrow$ acidic
$\mathrm{SnO}_2 \longrightarrow$ amphoteric

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main, JEE Main 2005
Which of the following oxides is expected to exhibit paramagnetic behaviour?

Options:
A $\mathrm{CO}_3$
B $\mathrm{SiO}_2$
C $\mathrm{SO}_2$
D $\mathrm{ClO}_2$

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

Solution:
$\mathrm{ClO}_2$ shows paramagnetic character due to presence of unpaired electron.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following oxides is not expected to react with sodium hydroxide ?

Options:
A $\mathrm{BeO}$
B $\mathrm{B}_2 \mathrm{O}_3$
C $\mathrm{CaO}$
D $\mathrm{SiO}_2$

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

Solution:
Since $\mathrm{CaO}$ itself is basic, It will not react with $\mathrm{NaOH}$

Topic: Chemistry, Electrochemistry, NEET, NEET 2009 (Mains)
Which of the following oxides is strongly basic?

Options:
A $\mathrm{Tl}_{2} \mathrm{O}$
B $\mathrm{B}_{2} \mathrm{O}_{3}$
C $\mathrm{Al}_{2} \mathrm{O}_{3}$
D $\mathrm{Ga}_{2} \mathrm{O}_{3}$

The correct answer is:
$\mathrm{B}_{2} \mathrm{O}_{3}$

Solution:
On moving down the group, the nature of the oxides of group 13 elements changes from weakly acidic to amphoteric and amphoteric to basic. $\mathrm{Tl}_{2} \mathrm{O}$ in aqueous solution gives $\mathrm{TlOH}$ which soluble and a strong base.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following oxides of nitrogen is the anhydride of nitrous acid

Options:
A $\mathrm{NO}$
B $\mathrm{N}_2 \mathrm{O}_3$
C $\mathrm{N}_2 \mathrm{O}_4$
D $\mathrm{N}_2 \mathrm{O}_5$

The correct answer is:
$\mathrm{N}_2 \mathrm{O}_3$

Solution:
$2 \mathrm{HNO}_2 \rightarrow \mathrm{H}_2 \mathrm{O}+\mathrm{N}_2 \mathrm{O}_3$

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following oxoacid of sulphur has - O- O- linkage?

Options:
A \( \mathrm{H}_{2} \mathrm{SO}_{4} \), sulphuric acid
B \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8} \), peroxodisulphuric acid
C \( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{7} \), pyrosulphuric acid
D \( \mathrm{H}_{2} \mathrm{SO}_{3} \), sulphurous acid

The correct answer is:
\( \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8} \), peroxodisulphuric acid

Solution:

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following oxoacids acts as best reducing agent?

Options:
A H3PO3
B H3PO4
C H4P2O6
D H4P2O7

The correct answer is:
H3PO3

Solution:
H-atom directly attached with 'P' atom is reducing in nature. H-atom attached with P atom through oxygen atom is acidic in nature.

Only orthophosphoric acid H3PO3 has H-atom directly attached with 'P' atom, therefore, it is reducing in nature. Rest other are oxidising agents.

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