datavorous/entrance-exam-dataset huggingface dataset:
Although chlorobenzene does not give Ullmann reaction. However presence of
group in chlorobenzene at
o-, p-position enables it to give Ullmann's reaction.

Options:
A \( \mathrm{NO}_{2} \)
B \( \mathrm{NH}_{2} \)
C \( \mathrm{OH} \)
D \( \mathrm{SO}_{3} \mathrm{H} \)

The correct answer is:
\( \mathrm{NO}_{2} \)

Solution:
–NO2 group being strongly electron withdrawing activates the ring towards reaction.

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main
Although $\mathrm{CN}^{-}$ion and $\mathrm{N}_2$ molecule are isoelectronic, yet $\mathrm{N}_2$ molecule is chemically inert because of

Options:
A
presence of more number of electrons in bonding orbitals

B
lone bond energy

C
absence of bond polarity

D
uneven electron distribution.

The correct answer is:
absence of bond polarity

Solution:
In nitrogen molecule, both the nitrogen atoms have same electronegativity. So it has zero polarity and hence less tendency to break away and form ions.

Topic: Chemistry, Chemical Bonding and Molecular Structure, JEE Main, JEE Main 2012 (12 May Online)
Although much CO2 is carried in blood, bloods does not become acidic because

Options:
A It is absorbed by the leucocytes
B Blood buffers play an important role in CO2 transport.
C It combines with water to from carbonic acid which is neutralized by NaCO3
D It is continuously diffused through tissues and is not allowed to accumulate

The correct answer is:
Blood buffers play an important role in CO2 transport.

Solution:
CO2 enters RBC and reacts with water to form carbonic acid. Carbonic acid dissociates to form bicarbonate and hydrogen ions. Some bicarbonate ions are transported in erythrocytes, while some diffuse into the blood plasma. Exit of bicarbonate ions changes the ionic balance between the plasma and erythrocytes. To restore this balance, chloride ions diffuse from plasma into erythrocytes. Due to this, the pH of blood is maintained.

Topic: Biology, Breathing and Exchange of Gases, NEET
Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than on phenol. Why?

Options:

None

Solution:
Consider the resonating structures of carboxylate ion and phenoxide ion:
In case of phenoxide ion, structures (II - IV) carry a negative charge on the less electronegative carbon atom. Therefore, their contribution towards the resonance stabilization of phenoxide ion is very small.
In structures I and II, (carboxylate ion), the negative charge is delocalized over two oxygen atoms while in structures I and V, the negative charge on the oxygen atom remains localized only the electrons of the benzene ring are delocalized. Since delocalization of benzene electrons contributes little towards the stability of phenoxide ion therefore, carboxylate ion is much more resonance stabilized than phenoxide ion. Thus, the release of a proton from carboxylic acids is much easier than from phenols. In other words, carboxylic acids are stronger acids than phenols.

Topic: Chemistry, Aldehydes, Ketones and Carboxylic Acids
Alum helps in purifying water by

Options:
A
forming Si complex with clay particles

B
sulphate part which combines with the dirt and removes it

C
coagulating the mud particles

D
making mud water soluble

The correct answer is:
coagulating the mud particles

Solution:
No Solution Available

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main, JEE Main 2002
Alumina is

Options:
A Acidic
B Basic
C Amphoteric
D None of these

The correct answer is:
Amphoteric

Solution:
Alumina is amphoteric oxide, which reacts acid as well as base.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminium chloride exists as dimer, $\mathrm{Al}_2 \mathrm{Cl}_6$ in solid state as well as in solution of non-polar solvents such as benzene. When dissolved in water, it gives

Options:
A $\left[\mathrm{Al} (\mathrm{OH})_5\right]^{3-}+3 \mathrm{HCl}$
B $\left[\mathrm{Al} \left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}+3 \mathrm{Cl}^{-}$
C $\mathrm{Al}^{3+}+3 \mathrm{Cl}^{-}$
D $\mathrm{Al}_2 \mathrm{O}_3+6 \mathrm{HCl}$

The correct answer is:
$\mathrm{Al}_2 \mathrm{O}_3+6 \mathrm{HCl}$

Solution:
$\mathrm{Al}_2 \mathrm{Cl}_6+12 \mathrm{H}_2 \mathrm{O} \rightleftharpoons 2\left[\mathrm{Al}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}+6 \mathrm{Cl}^{-}$

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminium chloride exists as dimer, $\mathrm{Al}_2 \mathrm{Cl}_6$ in solid state as well as in solution of non-polar solvents such as benzene. When dissolved in water, it gives

Options:
A
$\mathrm{Al}^{3+}+3 \mathrm{Cl}^{-}$

B
$\mathrm{Al}_2 \mathrm{O}_3+6 \mathrm{HCl}$

C
$\left[\mathrm{Al}(\mathrm{OH})_6\right]^{3-}$

D
$\left[\mathrm{Al}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}+3 \mathrm{Cl}^{-}$

The correct answer is:
$\left[\mathrm{Al}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}+3 \mathrm{Cl}^{-}$

Solution:
No Solution Available

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main, JEE Main 2004
Aluminium chloride in acidified aqueous solution forms an ion having geometry

Options:
A Octahedral
B Square Planar
C Tetrahedral
D Trigonal bipyramidal

The correct answer is:
Octahedral

Solution:
Aluminium Chloride in acidified aqueous solution forms octahedral Al(H2O)63+ ion.

AlCl3→Acidified aqueous solutionAlH2O63+

In this complex the 3d orbital of Al are involved and the hybridisation state of Al is sp3d2.

Hence, the answer is option A.

Topic: Chemistry, Coordination Compounds, JEE Main, JEE Main 2024 (30 Jan Shift 1)
Aluminium has a great affinity for oxygen and its oxidation is an exothermic process.This fact is made use of in

Options:
A Preparing thin foils of aluminium
B Making utensils
C Preparing duralumin alloy
D Thermite welding

The correct answer is:
Thermite welding

Solution:
Thermite Welding is based on the fact that
Aluminium has a great affinity for oxygen and its oxidation is an exothermic process.
Hence Option "4" is the correct answer.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminium (III) chloride forms a dimer because aluminium:

Options:
A Cannot form a trimer.
B Has high ionisation energy.
C Belongs to third group.
D Can have higher coordination number.

The correct answer is:
Can have higher coordination number.

Solution:
AlCl3 has a high coordination number. It exists in dimer form and the formula of the dimeric form is Al2Cl6â. It has vacant d-orbitals which can absorb electrons from the chlorine atom. It is an electron-deficient compound in Al (octet incomplete), so it acts as a Lewis acid, and Al completes it by taking an electron pair from Cl-atoms:

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminium (III) chloride forms a dimer because

Options:
A Higher coordination number can be achieved by aluminium
B Alumminium has high ionization energy
C Aluminium belongs to III group
D It cannot form a trimer

The correct answer is:
Higher coordination number can be achieved by aluminium

Solution:
$\mathrm{AlCl}_3$ can form dimer and exists as $\mathrm{Al}_2 \mathrm{Cl}_6$, aluminium has vacant d-orbitals which can accommodate electron from chlorine atom. $\mathrm{AlCl}_3$ is an electron deficient compound in $\mathrm{Al}$ (octet incomplete) thus behaves as Lewis acid and $\mathrm{Al}$ completes it by taking electron pair from $\mathrm{Cl}$-atom.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminium is extracted by the electrolysis of

Options:
A
bauxite

B
alumina

C
alumina mixed with molten cryolite

D
molten cryolite

The correct answer is:
alumina mixed with molten cryolite

Solution:
Alumina is mixed with cryolite which acts as an electrolyte

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main, JEE Main 2002
Aluminium is more reactive than iron. But aluminium is less easily corroded than iron because

Options:
A Aluminium is a noble metal
B Oxygen forms a protective oxide layer
C Iron undergoes reaction easily with water
D Iron forms mono and divalent ions

The correct answer is:
Oxygen forms a protective oxide layer

Solution:
Aluminium is reactive and yet less corrosive is because of a protective layer of Aluminium oxide which prevents further corrosion.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminium is not used

Options:
A In silvery paints
B For making utensils
C As a reducing agent
D As oxidizer in metallurgy

The correct answer is:
As oxidizer in metallurgy

Solution:
Aluminjum is used as reducing agent in metallurgy

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminium is obtained by

Options:
A Reducing $\mathrm{Al}_2 \mathrm{O}_3$ with coke
B Electrolysing $\mathrm{Al}_2 \mathrm{O}_3$ dissolved in $\mathrm{Na}_3 \mathrm{AlF}_6$
C Reducing $\mathrm{Al}_2 \mathrm{O}_3$ with chromium
D Heating alumina and cryolite

The correct answer is:
Electrolysing $\mathrm{Al}_2 \mathrm{O}_3$ dissolved in $\mathrm{Na}_3 \mathrm{AlF}_6$

Solution:
Aluminium is obtained by electrolising alumina dissolved in cryolite $\left(\mathrm{Na}_3 \mathrm{AlF}_6\right)$
$\begin{aligned} & 4 \mathrm{Na}_3 \mathrm{AlF}_6 \leftrightharpoons 12 \mathrm{Na}^{+}+4 \mathrm{Al}^{3+}+12 \mathrm{~F}^{-} \\ & 4 \mathrm{Al}^{3+}+12 \mathrm{e}^{-} \rightarrow 4 \mathrm{Al} \text { (at cathode) } \\ & 12 \mathrm{~F}^{-} \rightarrow 6 \mathrm{~F}_2+12 \mathrm{e}^{-} \text {(at anode) } \\ & 2 \mathrm{Al}_2 \mathrm{O}_3+6 \mathrm{~F}_2 \rightarrow \mathrm{AlF}_3+3 \mathrm{O}_2\end{aligned}$

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminium is usually found in +3 oxidation state. In contrast, thallium exists in +1 and +3 oxidation states. This is due to:

Options:
A Diagonal relationship
B Lattice effect
C Lanthanoid contraction
D Inert pair effect

The correct answer is:
Inert pair effect

Solution:
Reluctance in tendency of s-electrons to participate in bonding on moving top to bottom in p-block elements is called inert pair effect. Due to inert pair effect +1 is very unstable in aluminium.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2019 (09 Jan Shift 1)
Aluminium oxide is not reduced by chemical reactions since

Options:
A Aluminium oxide is reactive
B Reducing agents contaminate
C Aluminium oxide is highly stable
D The process pollutes the environment

The correct answer is:
Aluminium oxide is highly stable

Solution:
Aluminium oxide is highly stable therefore, it is not Reduced by chemical reactions.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminium oxide may be electrolysed at $1000^{\circ} \mathrm{C}$ to furnish aluminium metal (Atomic mass $=27$ amu; 1 Faraday $=96,500$ Coulombs). The cathode reaction is
$\mathrm{Al}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Al}^{\circ}$
To prepare $5.12 \mathrm{~kg}$ of aluminium metal by this method would require

Options:
A
$5.49 \times 10^7 \mathrm{C}$ of electricity

B
$1.83 \times 10^7$ C of electricity

C
$5.49 \times 10^4 \mathrm{C}$ of electricity

D
$5.49 \times 10^1 \mathrm{C}$ of electricity

The correct answer is:
$5.49 \times 10^7 \mathrm{C}$ of electricity

Solution:
$$
\begin{aligned}
& \mathrm{Q}=\frac{\mathrm{mFZ}}{\mathrm{M}}=\frac{5.12 \times 10^5 \times 96500 \times 3}{27} \\
& =5.49 \times 10^7 \mathrm{C}
\end{aligned}
$$

Topic: Chemistry, Electrochemistry, JEE Main, JEE Main 2005
Aluminium vessels should not be washed with materials containing washing soda since

Options:
A Washing soda is expensive
B Washing soda is easily decomposed
C Washing soda reacts with alluminium to form soluble aluminate
D Washing soda reacts with aluminium to form insoluble aluminium oxide

The correct answer is:
Washing soda reacts with alluminium to form soluble aluminate

Solution:
$\begin{aligned} & \mathrm{Na}_2 \mathrm{CO}_3+\mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{NaOH}+\mathrm{CO}_2 \\ & 2 \mathrm{NaOH}+2 \mathrm{Al}+6 \mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{Na}\left[\mathrm{Al}(\mathrm{OH})_4\right]+3 \mathrm{H}_2\end{aligned}$

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Alumino-thermite process is used for the extraction of metals, whose oxides are

Options:
A Fusible
B Not easily reduced by carbon
C Not easily reduced by hydrogen
D Strongly basic

The correct answer is:
Not easily reduced by carbon

Solution:
Alumino thermite process involves reduction of oxides such as Fe2O3,âMn3O4,âCr2O3 etc. to metals with aluminum.
Cr 2 O 3  + 2Al→ Al 2 O 3  + 2Cr;  ΔH = −ve

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Aluminum carbide Al4C3 liberates methane on treatment with water. The grams of aluminum carbide required to produce 11.2 L of methane under STP conditions is [Given Al = 27 ]

Options:
A 48
B 72
C 144
D 24

The correct answer is:
24

Solution:
Al4C3+12H2O→3CH4+4AlOH3
So 67.2 L CH4 evolved by 144 g Al4C3
11.2 L CH4 will be evolved = 144 67.2 ×11.2=24 g

Topic: Chemistry, Some Basic Concepts of Chemistry, JEE Main
Alzhimer disease in humans is associated with the deficiency of :

Options:
A Gamma aminobutyric acid (GABA)
B Dopamine
C Glutamic acid
D Acetylcholine

The correct answer is:
Acetylcholine

Solution:
No Solution Available

Topic: Biology, Neural Control and Coordination, NEET, NEET 2009 (Mains)
Amazon rain forests are considered as 'lungs of the planet' as they contribute _____ of the total oxygen in the Earth's atmosphere.

Options:
A 10%
B 15%
C 20%
D 30%

The correct answer is:
20%

Solution:
The tropical Amazonian rain forest in South America has the greatest diversity.
Tropical habitats are relatively more constant and less seasonal. Such environments tend to promote niche specialization that gives more diversity. Also, such environments remain undisturbed for millions of years leading to evolution and species diversification.
Amazon rain forests are considered as 'lungs of the planet' as they contribute 20% of the total oxygen in the Earth's atmosphere.

Topic: Biology, Organisms and Populations, NEET
Amensalism is an association between two species where

Options:
A
one species is harmed and other is benefited

B
one species is harmed and other is unaffected

C
one species is benefited and other is unaffected

D
both the species are harmed.

The correct answer is:
one species is harmed and other is unaffected

Solution:
When one species is harmed or destoryed and other remains unaffected in an association between two species, it is called amensalism. In commensalism, one species is benefited and other is unaffected.
The other options are incorrect because when one species is harmed and other is benefited, the relationship is termed as parasitism.

Topic: Biology, Organisms and Populations
Amensalism is an association between two species where

Options:
A one species is harmed and other is benefitted
B one species is harmed and other is unaffected
C one species is benefitted and other is unaffected
D both the species are harmed

The correct answer is:
one species is harmed and other is unaffected

Solution:
In a species interaction where one species benefits by harming the other is referred to as parasitism.
Ammensalism is a type of biological association between two organisms where one of the two remains unaffected while the other is adversely affected by the relationship.
Classic example ammensalism is displayed between fungus Penicillium and bacteria, where Penicillium secretes antibiotic that inhibits the growth of bacteria (adversely affected) and Penicillium remains unaffected. Another example is between the black walnut (Juglans nigra), which secretes juglone, a substance that destroys many herbaceous plants within its root zone.

Topic: Biology, Organisms and Populations, NEET
Amides are formed by the reaction of acid chloride with

Options:
A \( \mathrm{NH}_{2} \mathrm{NH}_{2} \)
B \( \mathrm{NH}_{3} \)
C \( \mathrm{NH}_{2} \mathrm{OH} \)
D \( \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHNH}_{2} \)

The correct answer is:
\( \mathrm{NH}_{3} \)

Solution:
It is the acyl substitution reaction. In which Cl atom is replaced by -NH2 group.

Nucleophile ammonia attacks at the electrophilic carbon of acid halide.

Addition-elimination reaction takes place and product is amide formed after removal of leaving group HCl

RCO-Cl+H-NH2→R-CONH2+HCl

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Amino acid Leucine is coded by 6 triplet codons: UUA, UUG, CUU, CUC, CUA and CUG.

Which of the following is most relevant for the statement given?

Options:
A Codes are non-overlapping
B Degeneracy of code
C Codes are commaless
D Three adjacent nitrogen bases specifies one amino acid

The correct answer is:
Degeneracy of code

Solution:
The genetic code is degenerate mainly at the third codon position. However, the reason for the degeneracy still remains unknown. The genetic code is degenerate because there are many instances in which different codons specify the same amino acid. Genetic codes in which some amino acids may be coded by more than one codon represent degeneracy of codon.

Topic: Biology, Molecular Basis of Inheritance, NEET
Amino acids are produced on hydrolysis of

Options:
A Nucleic acid
B Carbohydrates
C Fats
D Proteins

The correct answer is:
Proteins

Solution:
Amino acids are produced on hydrolysis of proteins

Topic: Chemistry, Biomolecules, JEE Main
Amino acids are

Options:
A Liquids
B Volatile solids
C Non-volatile crystalline compounds
D Mixture of amines and acids

The correct answer is:
Non-volatile crystalline compounds

Solution:
Amino acids are non volatile crystalline compound

Topic: Chemistry, Biomolecules, JEE Main
Amino acids usually exist in the form of Zwitter ions. This means that it consists of

Options:
A The basic group $-\mathrm{NH}_2$ and the acidic group $-\mathrm{COOH}$
B The basic group $-\mathrm{NH}_3^{+}$and the acidic group $\mathrm{CO}_2$
C The basic group $-\mathrm{CO}_2^{-}$and the acidic group $\mathrm{NH}_3^{+}$
D No acidic or basic group

The correct answer is:
The basic group $-\mathrm{CO}_2^{-}$and the acidic group $\mathrm{NH}_3^{+}$

Solution:
Zwitter ion is a dipolar ion containing both a positive and negative charge in the following form
The basic group $\mathrm{CO}_2^{-}$and acidic group $\mathrm{NH}_3^{+}$

Topic: Chemistry, Biomolecules, JEE Main
Aminoglycosides are usually used as:

Options:
A
antibiotic

B
analgesic

C
hypnotic

D
antifertility

The correct answer is:
antibiotic

Solution:
The aminoglycosides are among the oldest antibiotics.

Topic: Chemistry, Chemistry in Everyday Life, JEE Main, JEE Main 2014 (12 Apr Online)
Ammonia forms the complex [Cu(NH3)4]2+ with copper ions in alkaline solution but not in acidic solution. The reason for this is

Options:
A In alkaline solution Cu(OH)2 is precipitated which is soluble in excess of alkali
B Copper hydroxide is amphoteric substance
C In acidic solution hydration protects Cu2+ ions
D In acidic solution protons are coordinated with ammonia molecules forming NH4+ ions

The correct answer is:
In acidic solution protons are coordinated with ammonia molecules forming NH4+ ions

Solution:
Ammonia forms the complex CuNH342+ with copper ions in alkaline solution but not in acidic solution. The reason for this is In acidic solution protons are coordinated with ammonia molecules forming NH4+ ions.
Cu2+aq+4NH3âCuNH342+
Cu 2+  +  4NH 4 + → No complex formation

Topic: Chemistry, Coordination Compounds, JEE Main
Ammonia forms the complex ion $\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}$ with copper ions in alkaline solutions but not in acidic solutions. What is the reason for it?

Options:
A In acidic solutions protons coordinate with ammonia molecules forming $\mathrm{NH}_{4}^{+}$ ions and $\mathrm{NH}_{3}$ molecules are not available.
B In alkaline solutions insoluble $\mathrm{Cu}(\mathrm{OH})_{2}$ is precipitated which is soluble in excess of any alkali.
C Copper hydroxide is an amphoteric substance.
D In acidic solutions hydration protects copper ions.

The correct answer is:
In acidic solutions protons coordinate with ammonia molecules forming $\mathrm{NH}_{4}^{+}$ ions and $\mathrm{NH}_{3}$ molecules are not available.

Solution:
$\quad \mathrm{N} \mathrm{H}_{3}+\mathrm{H}^{+}$ (acidic medium) $\rightleftharpoons \mathrm{NH}_{4}^{+}$

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Ammonia forms the complex ion $\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right]^{2+}$ with copper ions in alkaline solutions but not in acidic solutions. What is the reason for it?

Options:
A
In acidic solutions protons coordinate with ammonia molecules forming $\mathrm{NH}_4^{+}$ions and $\mathrm{NH}_3$ molecules are not available

B
In alkaline solutions insoluble $\mathrm{Cu}(\mathrm{OH})_2$ is precipitated which is soluble in excess of any alkali

C
Copper hydroxide is an amphoteric substance

D
In acidic solutions hydration protects copper ions.

The correct answer is:
In acidic solutions protons coordinate with ammonia molecules forming $\mathrm{NH}_4^{+}$ions and $\mathrm{NH}_3$ molecules are not available

Solution:
No Solution Available

Topic: Chemistry, Coordination Compounds, JEE Main, JEE Main 2003
Ammonia gas can be collected by the displacement of

Options:
A Conc. $\mathrm{H}_2 \mathrm{SO}_4$
B Brine
C Water
D Mercury

The correct answer is:
Mercury

Solution:
Ammonia is less dense than air hence can be collected by upward displacement of air and mercury.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Ammonia reacts with excess of chlorine to form

Options:
A $\mathrm{N}_2$ and $\mathrm{HCl}$
B $\mathrm{NH}_4 \mathrm{Cl}$ and $\mathrm{NCl}_3$
C $\mathrm{NCl}_3$ and $\mathrm{HCl}$
D $\mathrm{N}_2$ and $\mathrm{NH}_4 \mathrm{Cl}$

The correct answer is:
$\mathrm{NCl}_3$ and $\mathrm{HCl}$

Solution:
$\mathrm{NH}_3+3 \mathrm{Cl}_2 \rightarrow \mathrm{NCl}_3 +3 \mathrm{HCl}$

Topic: Chemistry, Practical Chemistry, JEE Main
Ammonium carbonate decomposes as

NH2COONH4sâ2NH3g+CO2(g)

For the reaction, Kp=2.9Ã10-5 atm3. If we start with 1 mole of the compound, the total pressure at equilibrium would be

Options:
A 0.766 atm
B 0.0582 atm
C 0.0388 atm
D 0.0194 atm

The correct answer is:
0.0582 atm

Solution:
NH2COONH4sâ2NH3g+CO2(g)
At equilibrium if partial pressure of CO2 is p then that of NH3 is 2p
So, K p = p NH 3 2 Ã p CO 2
K p = 2 p 2 Ã p = 4 p 3
2.9 Ã 10 - 5 = 4 p 3
p = 1.935 Ã 10 - 2
hence, total pressure p=3p
=5.81Ã10-2=0.0581 atm.

Topic: Chemistry, Chemical Equilibrium, JEE Main
Ammonium carbonate dissociates as
NH 2 COONH 4 (s) ⇌  2NH 3 (g) +  CO 2 (g)
In a closed vessel having ammonium carbonate in equilibrium NH3 is added such that partial pressure of NH3 now to equals to the original total pressure. The ratio of total pressure now the original pressure is?

Options:
A 2731
B 3127
C 49
D 319

The correct answer is:
3127

Solution:
NH 2 COONH 4 (s) ⇌  2NH 3 (g) +  CO 2 (g)
Suppose P is pressure of CO2 at equilibrium than
PNH3=2P
PTotal=2P+P=3P
As KP=PNH32PCO2=4P3
On adding NH3 at equilibrium
PNH3=PTotal=3P
So KP=4P3=PNH32.P'CO2
4P3=3P2P'CO2
P'CO2=49P
Now total P'=3P+49P=319P
Hence pressure ratio P'P=319P3P
=3127

Topic: Chemistry, Chemical Equilibrium, JEE Main
Ammonium chloride crystallizes in a body centred cubic lattice with edge length of unit cell of 390 $\mathrm{pm}$. If the size of chloride ion is $180 \mathrm{pm}$, the size of ammonium ion would be

Options:
A
$174 \mathrm{pm}$

B
$158 \mathrm{pm}$

C
$142 \mathrm{pm}$

D
$126 \mathrm{pm}$

The correct answer is:
$158 \mathrm{pm}$

Solution:
For bcc structure
$$
\begin{aligned}
\text { Interionic distance }= & r^{+}+r^{-}=\frac{\sqrt{3}}{2} a \\
& (a=\text { edge length })
\end{aligned}
$$
$$
\begin{aligned}
& r_{\mathrm{NH}_4^{+}}^{+}+r_{\mathrm{Cl}^{-}}^{-}=\frac{\sqrt{3}}{2} a \\
& r_{\mathrm{NH}_4^{+}}^{+}+180=\frac{\sqrt{3}}{2} \times 390
\end{aligned}
$$
$$
\mathrm{r}_{\mathrm{NH}_4^{+}}^{+}=338 \mathrm{pm}-180 \mathrm{pm}=158 \mathrm{pm}
$$

Topic: Chemistry, Solid State, JEE Main, JEE Main 2012 (19 May Online)
Ammonium dichromate is used in some fireworks. The green coloured powder blown in the air is

Options:
A CrO 3
B Cr
C CO
D Cr 2 O 3

The correct answer is:
Cr 2 O 3

Solution:
Ammonium dichromate [ ( NH 4 ) 2 Cr 2 O 7 ] on heating decomposes producing green powder of Cr 2 O 3 and N 2 ( g ) is evolved.

Topic: Chemistry, d and f Block Elements, JEE Main