Major Competitive Exams
Q. Which of the following groups is a weak -I effect?
A.
-CH3
B.
-Cl
C.
-Br
D.
-I
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Solution
The -CH3 group exhibits a weak -I effect as it is a weak electron-donating group.
Correct Answer: A — -CH3
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Q. Which of the following groups is a weak -M group?
A.
-CHO
B.
-COOH
C.
-NO2
D.
-F
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Solution
-F is a weak -M group as it has a slight electron-withdrawing effect but is not as strong as -CHO or -COOH.
Correct Answer: D — -F
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Q. Which of the following groups is characterized by the presence of a nucleus? (2023)
A.
Bacteria
B.
Archaea
C.
Eukarya
D.
Monera
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Solution
Eukarya is characterized by the presence of a true nucleus in its cells.
Correct Answer: C — Eukarya
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Q. Which of the following groups is considered a weak -I group?
A.
-NO2
B.
-CN
C.
-F
D.
-COOH
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Solution
-F is considered a weak -I group compared to -NO2 and -CN.
Correct Answer: C — -F
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Q. Which of the following groups is known for its +I effect?
A.
-CH3
B.
-OH
C.
-NO2
D.
-COOH
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Solution
-CH3 exhibits a +I effect as it donates electron density through inductive effect.
Correct Answer: A — -CH3
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Q. Which of the following groups of animals is characterized by having feathers? (2021)
A.
Mammals
B.
Reptiles
C.
Birds
D.
Amphibians
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Solution
Birds are the only group of animals that possess feathers, which are essential for flight and insulation.
Correct Answer: C — Birds
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Q. Which of the following groups of organisms is classified under the kingdom Protista? (2018)
A.
Mushrooms
B.
Algae
C.
Worms
D.
Insects
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Solution
Algae are classified under the kingdom Protista.
Correct Answer: B — Algae
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Q. Which of the following groups of plants is known for producing seeds? (2023)
A.
Mosses
B.
Ferns
C.
Gymnosperms
D.
Liverworts
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Solution
Gymnosperms are known for producing seeds, which are not enclosed in an ovary.
Correct Answer: C — Gymnosperms
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Q. Which of the following groups of plants is known for producing spores? (2021)
A.
Angiosperms
B.
Gymnosperms
C.
Pteridophytes
D.
Bryophytes
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Solution
Pteridophytes are known for producing spores as a means of reproduction.
Correct Answer: C — Pteridophytes
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Q. Which of the following groups shows +M effect?
A.
-NO2
B.
-CN
C.
-OCH3
D.
-COOH
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Solution
The -OCH3 group shows +M effect as it donates electrons through resonance.
Correct Answer: C — -OCH3
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Q. Which of the following groups shows a +M effect?
A.
–NO2
B.
–F
C.
–OH
D.
–CN
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Solution
The –OH group donates electron density through resonance, exhibiting a +M effect.
Correct Answer: C — –OH
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Q. Which of the following groups would decrease the electron density on a benzene ring?
A.
-OCH3
B.
-NO2
C.
-CH3
D.
-Cl
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Solution
-NO2 is a strong electron-withdrawing group that decreases electron density on the benzene ring.
Correct Answer: B — -NO2
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Q. Which of the following haloalkanes can be converted to an alcohol by hydrolysis?
A.
Bromobenzene
B.
Chloroethane
C.
Iodobutane
D.
All of the above
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Solution
Iodobutane can be converted to an alcohol by hydrolysis, while bromobenzene requires a different mechanism due to its aromatic nature.
Correct Answer: C — Iodobutane
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Q. Which of the following haloalkanes can undergo elimination reaction to form an alkene? (2021)
A.
1-bromopropane
B.
2-bromobutane
C.
Bromobenzene
D.
Chloroethane
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Solution
2-bromobutane can undergo elimination to form an alkene due to the presence of a beta-hydrogen.
Correct Answer: B — 2-bromobutane
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Q. Which of the following haloalkanes is expected to have the highest boiling point?
A.
Chloroethane
B.
Bromoethane
C.
Iodoethane
D.
Fluoroethane
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Solution
Iodoethane has the highest boiling point due to the larger size and polarizability of iodine.
Correct Answer: C — Iodoethane
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Q. Which of the following haloalkanes is least soluble in water?
A.
Chloroethane
B.
Bromoethane
C.
Iodoethane
D.
Fluoroethane
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Solution
Iodoethane is least soluble in water due to its larger size and lower polarity compared to the others.
Correct Answer: C — Iodoethane
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Q. Which of the following haloalkanes is most reactive towards nucleophilic substitution?
A.
1-bromopropane
B.
2-bromopropane
C.
3-bromopropane
D.
Bromobenzene
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Solution
3-bromopropane is more reactive due to the stability of the tertiary carbocation formed during the reaction.
Correct Answer: C — 3-bromopropane
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Q. Which of the following haloalkanes is the most reactive towards nucleophilic substitution?
A.
1-bromopropane
B.
2-bromopropane
C.
3-bromopropane
D.
bromobenzene
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Solution
3-bromopropane is a tertiary haloalkane, which is more reactive towards nucleophilic substitution due to steric hindrance and stability of the carbocation formed.
Correct Answer: C — 3-bromopropane
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Q. Which of the following haloalkanes will undergo elimination reaction more readily?
A.
1-chloropropane
B.
2-chloropropane
C.
3-chloropropane
D.
chlorobenzene
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Solution
3-chloropropane is a tertiary haloalkane and will undergo elimination more readily due to the stability of the resulting alkene.
Correct Answer: C — 3-chloropropane
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Q. Which of the following haloalkanes will undergo elimination reaction most readily?
A.
1-bromopropane
B.
2-bromopropane
C.
3-bromopropane
D.
bromobenzene
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Solution
2-bromopropane undergoes elimination readily due to the formation of a stable alkene.
Correct Answer: C — 3-bromopropane
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Q. Which of the following haloarenes can undergo nucleophilic substitution?
A.
Chlorobenzene
B.
Bromobenzene
C.
Iodobenzene
D.
All of the above
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Solution
All of the listed haloarenes can undergo nucleophilic substitution under suitable conditions.
Correct Answer: D — All of the above
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Q. Which of the following haloarenes is most reactive in nucleophilic aromatic substitution?
A.
Chlorobenzene
B.
Bromobenzene
C.
Nitrochlorobenzene
D.
Fluorobenzene
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Solution
Nitrochlorobenzene is most reactive due to the electron-withdrawing nitro group, which stabilizes the negative charge in the intermediate.
Correct Answer: C — Nitrochlorobenzene
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Q. Which of the following haloarenes is most reactive towards nucleophilic substitution?
A.
Chlorobenzene
B.
Bromobenzene
C.
Iodobenzene
D.
Fluorobenzene
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Solution
Iodobenzene is the most reactive towards nucleophilic substitution due to the weaker C-I bond compared to the other haloarenes.
Correct Answer: C — Iodobenzene
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Q. Which of the following has 3 significant figures?
A.
0.00234
B.
23.40
C.
1000
D.
0.0450
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Solution
23.40 has 4 significant figures, while 0.0450 has 3.
Correct Answer: B — 23.40
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Q. Which of the following has 4 significant figures?
A.
0.0025
B.
2500
C.
25.00
D.
0.250
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Solution
25.00 has 4 significant figures due to the trailing zeros.
Correct Answer: C — 25.00
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Q. Which of the following has a bent molecular geometry?
A.
CO2
B.
H2O
C.
CH4
D.
BF3
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Solution
H2O has two lone pairs and two bonding pairs, resulting in a bent geometry.
Correct Answer: B — H2O
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Q. Which of the following has a bond angle of approximately 120 degrees?
A.
H2O
B.
NH3
C.
BF3
D.
CH4
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Solution
BF3 has a trigonal planar geometry with bond angles of approximately 120 degrees.
Correct Answer: C — BF3
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Q. Which of the following has a bond order of 0?
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Solution
He2 has a bond order of 0, calculated as (2 bonding electrons - 2 antibonding electrons)/2 = 0.
Correct Answer: A — He2
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Q. Which of the following has a bond order of 1?
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Solution
H2 has a bond order of 1, calculated as (2 bonding electrons - 0 antibonding electrons)/2 = 1.
Correct Answer: C — H2
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Q. Which of the following has a central atom with dsp3 hybridization?
A.
PCl5
B.
XeF4
C.
NH4+
D.
C2H2
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Solution
In PCl5, the phosphorus atom is dsp3 hybridized, resulting in a trigonal bipyramidal geometry.
Correct Answer: A — PCl5
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