Major Competitive Exams
Q. Which of the following compounds is responsible for ozone layer depletion? (2019)
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A.
Methane
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B.
Chlorofluorocarbons (CFCs)
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C.
Carbon Dioxide
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D.
Nitrous Oxide
Solution
Chlorofluorocarbons (CFCs) are known to deplete the ozone layer by breaking down ozone molecules in the stratosphere.
Correct Answer: B — Chlorofluorocarbons (CFCs)
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Q. Which of the following compounds is stabilized by +M effect?
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A.
Phenol
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B.
Acetic acid
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C.
Nitrobenzene
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D.
Benzaldehyde
Solution
Phenol is stabilized by the +M effect due to the presence of the -OH group which donates electron density.
Correct Answer: A — Phenol
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Q. Which of the following compounds is the most acidic?
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A.
Ethylene
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B.
Propene
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C.
Propyne
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D.
Butyne
Solution
Propyne is the most acidic due to the sp hybridization of the carbon atom involved in the triple bond.
Correct Answer: C — Propyne
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Q. Which of the following compounds is used as a catalyst in the Haber process?
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A.
Iron(III) oxide
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B.
Nickel
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C.
Iron
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D.
Cobalt
Solution
Iron is used as a catalyst in the Haber process for the synthesis of ammonia from nitrogen and hydrogen.
Correct Answer: C — Iron
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Q. Which of the following compounds is used as a flavoring agent in food?
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A.
Vanillin
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B.
Acetic acid
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C.
Sodium chloride
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D.
Citric acid
Solution
Vanillin is the primary component of the extract of the vanilla bean and is used as a flavoring agent.
Correct Answer: A — Vanillin
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Q. Which of the following compounds is used as a food colorant?
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A.
Carotenoids
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B.
Sodium chloride
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C.
Vinegar
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D.
Citric acid
Solution
Carotenoids are natural pigments used as food colorants.
Correct Answer: A — Carotenoids
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Q. Which of the following compounds is used as a reducing agent?
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A.
KMnO4
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B.
H2SO4
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C.
NaBH4
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D.
HCl
Solution
Sodium borohydride (NaBH4) is commonly used as a reducing agent.
Correct Answer: C — NaBH4
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Q. Which of the following compounds is used as a sweetener?
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A.
Aspartame
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B.
Sodium chloride
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C.
Vinegar
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D.
Citric acid
Solution
Aspartame is a widely used artificial sweetener in many food products.
Correct Answer: A — Aspartame
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Q. Which of the following compounds is used in the treatment of heartburn?
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A.
Sodium bicarbonate
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B.
Calcium carbonate
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C.
Magnesium hydroxide
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D.
All of the above
Solution
All of the listed compounds are antacids used to treat heartburn.
Correct Answer: D — All of the above
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Q. Which of the following compounds shows both -I and +M effects?
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A.
Acetic acid
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B.
Nitrobenzene
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C.
Anisole
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D.
Benzaldehyde
Solution
Benzaldehyde shows a -I effect due to the carbonyl group and a +M effect due to the aromatic ring.
Correct Answer: D — Benzaldehyde
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Q. Which of the following compounds will be most stable due to resonance?
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A.
C6H5NO2
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B.
C6H5Cl
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C.
C6H5OH
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D.
C6H5CH3
Solution
C6H5NO2 is most stable due to the strong electron-withdrawing effect of the -NO2 group, which stabilizes the negative charge through resonance.
Correct Answer: A — C6H5NO2
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Q. Which of the following compounds will have the highest boiling point when dissolved in water?
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A.
NaCl
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B.
KBr
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C.
MgCl2
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D.
LiI
Solution
MgCl2 dissociates into 3 ions (1 Mg²⁺ and 2 Cl⁻), leading to the highest boiling point elevation due to the greatest number of particles.
Correct Answer: C — MgCl2
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Q. Which of the following compounds will have the highest electron density at the ortho position due to +M effect?
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A.
C6H5NO2
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B.
C6H5OH
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C.
C6H5Cl
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D.
C6H5CH3
Solution
C6H5OH has the highest electron density at the ortho position due to the +M effect of the -OH group.
Correct Answer: B — C6H5OH
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Q. Which of the following compounds will have the highest electron density due to +M effect?
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A.
Phenol
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B.
Benzaldehyde
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C.
Nitrobenzene
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D.
Aniline
Solution
Aniline has the highest electron density due to the +M effect of the amino group.
Correct Answer: D — Aniline
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Q. Which of the following compounds will undergo nucleophilic substitution via an SN1 mechanism?
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A.
1-chloropropane
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B.
2-chloropropane
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C.
3-chloropropane
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D.
chlorobenzene
Solution
3-chloropropane is a tertiary haloalkane, which favors the SN1 mechanism due to the formation of a stable tertiary carbocation.
Correct Answer: C — 3-chloropropane
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Q. Which of the following compounds would be most acidic due to the inductive effect?
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A.
CH3COOH
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B.
ClCH2COOH
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C.
FCH2COOH
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D.
BrCH2COOH
Solution
FCH2COOH is the most acidic due to the strong -I effect of the fluorine atom.
Correct Answer: C — FCH2COOH
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Q. Which of the following compounds would be most stabilized by +M effect?
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A.
Phenol
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B.
Acetic acid
-
C.
Chloroethane
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D.
Nitrobenzene
Solution
Phenol is stabilized by the +M effect due to the presence of the -OH group, which donates electron density.
Correct Answer: A — Phenol
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Q. Which of the following conditions is necessary for total internal reflection to occur?
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A.
Light must travel from a denser to a rarer medium
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B.
Light must travel from a rarer to a denser medium
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C.
The angle of incidence must be less than the critical angle
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D.
The angle of incidence must be equal to the critical angle
Solution
Total internal reflection occurs only when light travels from a denser medium to a rarer medium and the angle of incidence exceeds the critical angle.
Correct Answer: A — Light must travel from a denser to a rarer medium
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Q. Which of the following conditions must be satisfied for a rigid body to be in static equilibrium?
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A.
Sum of forces is zero and sum of moments is zero
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B.
Only sum of forces is zero
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C.
Only sum of moments is zero
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D.
Sum of forces and moments can be non-zero
Solution
A rigid body is in static equilibrium when both the sum of forces and the sum of moments about any point are zero.
Correct Answer: A — Sum of forces is zero and sum of moments is zero
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Q. Which of the following conditions must be satisfied for total internal reflection to occur?
-
A.
Light must travel from a denser to a rarer medium.
-
B.
Light must travel from a rarer to a denser medium.
-
C.
The angle of incidence must be less than the critical angle.
-
D.
The angle of incidence must be equal to the critical angle.
Solution
Total internal reflection occurs when light travels from a denser medium to a rarer medium and the angle of incidence exceeds the critical angle.
Correct Answer: A — Light must travel from a denser to a rarer medium.
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Q. Which of the following conditions will favor the spontaneity of a reaction?
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A.
High ΔH and low ΔS
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B.
Low ΔH and high ΔS
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C.
High ΔH and high ΔS
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D.
Low ΔH and low ΔS
Solution
A reaction is favored when it has low ΔH (exothermic) and high ΔS (increased disorder).
Correct Answer: B — Low ΔH and high ΔS
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Q. Which of the following conditions will lead to a decrease in Gibbs Free Energy?
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A.
Increasing temperature for an exothermic reaction.
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B.
Decreasing entropy.
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C.
Increasing pressure for a gas-phase reaction.
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D.
Increasing ΔH.
Solution
Increasing temperature for an exothermic reaction (ΔH < 0) can lead to a decrease in Gibbs Free Energy, making the reaction more spontaneous.
Correct Answer: A — Increasing temperature for an exothermic reaction.
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Q. Which of the following conditions will lead to a negative ΔG?
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A.
High temperature and low ΔH
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B.
Low temperature and high ΔH
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C.
High temperature and high ΔS
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D.
Low temperature and low ΔS
Solution
A high temperature and high ΔS will favor a negative ΔG, making the process spontaneous.
Correct Answer: C — High temperature and high ΔS
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Q. Which of the following conditions will lead to a positive ΔG?
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A.
High temperature and low entropy.
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B.
Low temperature and high enthalpy.
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C.
High temperature and high entropy.
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D.
Low temperature and low enthalpy.
Solution
A positive ΔG can occur at low temperatures when the enthalpy is high, making the reaction non-spontaneous.
Correct Answer: B — Low temperature and high enthalpy.
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Q. Which of the following conditions will lead to a spontaneous reaction?
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A.
ΔH > 0 and ΔS < 0
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B.
ΔH < 0 and ΔS > 0
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C.
ΔH > 0 and ΔS > 0
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D.
ΔH < 0 and ΔS < 0
Solution
A spontaneous reaction occurs when ΔG < 0. This is true for ΔH < 0 and ΔS > 0, as it leads to a negative ΔG.
Correct Answer: B — ΔH < 0 and ΔS > 0
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Q. Which of the following configurations can be analyzed using Ampere's Law?
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A.
A point charge
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B.
A charged capacitor
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C.
A long straight wire
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D.
A dipole
Solution
Ampere's Law is applicable to configurations with symmetry, such as a long straight wire carrying current.
Correct Answer: C — A long straight wire
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Q. Which of the following configurations can be used to create a Wheatstone bridge?
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A.
Series only
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B.
Parallel only
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C.
Series and parallel
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D.
None of the above
Solution
A Wheatstone bridge can be formed using a combination of series and parallel resistors.
Correct Answer: C — Series and parallel
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Q. Which of the following configurations is incorrect?
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A.
1s2 2s2 2p6 3s2
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B.
1s2 2s2 2p6 3s2 3p6
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C.
1s2 2s2 2p6 3s2 3p1
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D.
1s2 2s2 2p6 3s2 3p5
Solution
The configuration 1s2 2s2 2p6 3s2 3p6 is incorrect as it exceeds the maximum number of electrons in the 3rd shell.
Correct Answer: B — 1s2 2s2 2p6 3s2 3p6
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Q. Which of the following configurations represents a noble gas?
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A.
1s2 2s2 2p6
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B.
1s2 2s2 2p5
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C.
1s2 2s2 2p4
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D.
1s2 2s2 2p3
Solution
The configuration 1s2 2s2 2p6 corresponds to Neon, a noble gas.
Correct Answer: A — 1s2 2s2 2p6
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Q. Which of the following configurations represents a transition metal?
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A.
[Ar] 4s2 3d10
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B.
[Ne] 3s2 3p6
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C.
[Kr] 5s2 4d5
-
D.
[Xe] 6s2
Solution
The configuration [Kr] 5s2 4d5 represents Molybdenum (Mo), a transition metal.
Correct Answer: C — [Kr] 5s2 4d5
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