Dive into today’s quiz part 2 on fundamentals of organic chemistry—perfect for MDCAT & ECAT aspirants. I hope you enjoy learning here as much as I enjoy teaching. 🌟
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🔥 Ace MDCAT & ECAT MCQs Quiz: Master the Fundamentals of Organic Chemistry Part 2 ! 🔬💡 | Essential Insights on Basics like Homologous Series, Functional Group and Isomerism
1️⃣ Compounds having same molecular formula but different structural formulae are said to be:
🟩 A. Polymers
🟪 B. Isomers
🟨 C. Monomers
🟥 D. Dimers
2️⃣ Which one of the following is a type of isomerism?
🟩 A. Chain or skeletal
🟪 B. Stereo isomerism
🟨 C. Metamerism
🟥 D. All of them
3️⃣ Two or more than two compounds of the same molecular formula having different carbon skeletons or chains are said to be:
🟩 A. Chain isomers
🟪 B. Functional isomers
🟨 C. Position isomers
🟥 D. Metamers
4️⃣ Two or more compounds of the same molecular formula having different structural formulas due to different position of the same functional group or multiple bonds (in case of unsaturated compounds) are termed as:
🟩 A. Chain isomers
🟪 B. Functional group isomers
🟨 C. Position isomers
🟥 D. Metamers
5️⃣ Decane has ________ isomers:
🟩 A. 3
🟪 B. 9
🟨 C. 25
🟥 D. 75
🟩 A. Positional isomerism
🟪 B. Functional isomerism
🟨 C. Chain isomerism
🟥 D. All of these
🟩 A. 2
🟪 B. 3
🟨 C. 4
🟥 D. None
8️⃣ Two or more compounds of the same molecular formula having different alkyl radicals attached to the same polyvalent atom are termed as:
🟩 A. Chain isomers
🟪 B. Position isomers
🟨 C. Functional isomers
🟥 D. Metamers
9️⃣ Two or more compounds of the same molecular formula having different functional groups are called:
🟩 A. Chain isomers
🟪 B. Position isomers
🟨 C. Functional isomers
🟥 D. Metamers
🔟 Propylene oxide is isomeric with:
🟩 A. Propanoic acid
🟪 B. Propanone
🟨 C. Propene
🟥 D. Propanol
🟩 A. 2
🟪 B. 3
🟨 C. 4
🟥 D. 5
🟩 A. 2
🟪 B. 3
🟨 C. 4
🟥 D. 8
1️⃣3️⃣.Which type of isomerism is being exhibited by FCH=CHF?
🟩 A. Position isomerism
🟪 B. Structural isomerism
🟨 C. Geometrical isomerism
🟥 D. Chain isomerism
🟩 A. 2
🟪 B. 3
🟨 C. 5
🟥 D. 4
1️⃣5️⃣.Which isomerism is NOT shown by alkene?
🟩 A. Chain isomerism
🟪 B. Position isomerism
🟨 C. Geometrical isomerism
🟥 D. Metamerism
1️⃣6️⃣.Ethanol and dimethyl ether are best considered as:
🟩 A. Stereo isomers
🟪 B. Enantiomers
🟨 C. Structural isomers
🟥 D. Diastereomers
1️⃣7️⃣.Which type of isomerism is shown by ether?
🟩 A. Metamerism
🟪 B. Functional isomerism
🟨 C. Positional isomerism
🟥 D. Both A and B
1️⃣8️⃣ Type of isomerism in BrCH=CHBr is:
🟩 A. Structural
🟪 B. Conformational
🟨 C. Geometrical
🟥 D. Positional
1️⃣9️⃣ 2-chlorobutane & 1-chlorobutane are:
🟩 A. Positional isomers
🟪 B. Chain isomers
🟨 C. Geometrical
🟥 D. None
🟩 A. 5
🟪 B. 8
🟨 C. 6
🟥 D. 4
🟩 A. 3
🟪 B. 2
🟨 C. 4
🟥 D. 5
🟩 A. 4
🟪 B. 5
🟨 C. 6
🟥 D. 7
🟩 A. 4
🟪 B. 3
🟨 C. 2
🟥 D. 7
2️⃣4️⃣.The phenomenon involving the migration of a proton to give two structural isomers in equilibrium with each other is known as:
🟩 A. Matamerism
🟪 B. Stereo isomerism
🟨 C. Cis-trans isomerism
🟥 D. Tautomerism
🟩 A. 4
🟪 B. 5
🟨 C. 6
🟥 D. 7
2️⃣6️⃣.Which one of the following is an isomer of dimethyl ether?
🟩 A. (CH₃)₂CHOH
🟪 B. CH₃CH₂OH
🟨 C. CHO-CHO
🟥 D. None
🟩 A. 7
🟪 B. 6
🟨 C. 4
🟥 D. 5
🟩 A. 9
🟪 B. 3
🟨 C. 4
🟥 D. 5
🟩 A. 4
🟪 B. 5
🟨 C. 6
🟥 D. 7
🟩 A. 7
🟪 B. 6
🟨 C. 4
🟥 D. 5
🟩 A. Metamerism
🟪 B. Functional isomerism
🟨 C. Position isomerism
🟥 D. All types
3️⃣2️⃣ Metamerism is not shown by:
🟩 A. Esters
🟪 B. Ketones
🟨 C. Ethers
🟥 D. Alcohols
3️⃣3️⃣ An isomer of C₂H₅OH is:
🟩 A. CH₃OH
🟪 B. (C₂H₅)₂O
🟨 C. (CH₃)₂O
🟥 D. CH₃COCH₃
3️⃣4️⃣ The isomerism shown by alkanes is:
🟩 A. Skeletal
🟪 B. Position
🟨 C. Geometric
🟥 D. Metamerism
3️⃣5️⃣ Metamerism is shown by:
🟩 A. Amines
🟪 B. Ethers
🟨 C. Both of them
🟥 D. None of them
3️⃣6️⃣ Acetic acid and methyl formate are called:
🟩 A. Cis-trans isomers
🟪 B. Functional isomers
🟨 C. Position isomers
🟥 D. Metamers
3️⃣7️⃣Which of the following pairs of homologous series is represented by the general molecular formula CₙH₂ₙ₋₂?
🟩 A. Alkyne & alkadiene
🟪 B. Alkyne and alkadiyne
🟨 C. Alkane & alkadiene
🟥 D. Alkene & alkyne
3️⃣8️⃣ Isomerism which is present only in alkene is:
🟩 A. Metamerism
🟪 B. Structural isomerism
🟨 C. Cis-trans isomerism
🟥 D. Both B and C
3️⃣9️⃣Which of the following is the structure of the isobutyl alkyl radical?
🟩 A.
🟪 B.
🟨 C.
🟥 D.
4️⃣0️⃣Select which one shows cis-trans isomerism:
🟩 A. Cl₂C=CCl₂
🟪 B. H₂C=CH₂
🟨 C. ClCH=CHCl
🟥 D. Br₂C=CBr₂
4️⃣1️⃣ Pentane and 2-methylbutane have the same:
🟩 A. Boiling point
🟪 B. Percentage composition
🟨 C. Structural formula
🟥 D. Melting point
4️⃣2️⃣Geometrical isomerism is usually found in:
🟩 A. Alkanes
🟪 B. Alkenes
🟨 C. Alkynes
🟥 D. Esters
4️⃣3️⃣Propene can exhibit:
🟩 A. Cis-trans isomerism
🟪 B. Geometrical isomerism
🟨 C. Both A and B
🟥 D. None of them
4️⃣4️⃣ Which of the following is an aromatic compound?
🟩 A. Aniline
🟪 B. Cyclobutane
🟨 C. Cyclohexanol
🟥 D. Neopentane
4️⃣5️⃣There are two types of isomerism: structural isomerism and stereoisomerism. The two main types of stereoisomerism are diastereomerism (including 'cis-trans isomerism' and optical isomerism). Each non-superimposable mirror image structure is called a/an:
🟩 A. Metamer
🟪 B. Elastomer
🟨 C. Enantiomer
🟥 D. Tautomer
4️⃣6️⃣ All of the following compounds can exist in the form of cis and trans isomers EXCEPT:
🟩 A. 2-butene
🟪 B. 1-bromo-2-chloropropene
🟨 C. 2-pentene
🟥 D. 1-pentene
4️⃣7️⃣ Ethoxyethane and methoxylpropane show which of the following types of isomerism?
🟩 A. Metamerism
🟪 B. Cis-trans isomerism
🟨 C. Position isomerism
🟥 D. Tautomerism
4️⃣8️⃣ Ethanol and dimethyl ether are best described as:
🟩 A. Structural isomers
🟪 B. Enantiomers
🟨 C. Stereoisomers
🟥 D. Diastereomers
4️⃣9️⃣ The number of chain isomers of butene are:
🟩 A. Three
🟪 B. Two
🟨 C. One
🟥 D. Zero
5️⃣0️⃣ The number of positional isomers of butene are:
🟩 A. Three
🟪 B. Two
🟨 C. One
🟥 D. Zero
5️⃣1️⃣ Metamerism is shown by:
🟩 A. Thioethers
🟪 B. Secondary amides
🟨 C. Secondary amines
🟥 D. All of them
🟩 A. Amines
🟪 B. Esters
🟨 C. Thioethers
🟥 D. Acid halides
5️⃣3️⃣ Geometric isomerism is present in:
🟩 A. Ethane
🟪 B. Propane
🟨 C. 2-Butene
🟥 D. Methane
5️⃣4️⃣ Which of the following is not an isomer of but-1-yne?
🟩 A. Methylcyclopropene
🟪 B. But-1,3-diene
🟨 C. But-2-ene
🟥 D. But-2-yne
5️⃣5️⃣ The isomer of an oxime is:
🟩 A. RNO
🟪 B. R–O–C≡N
🟨 C. R–O–N=O
🟥 D. RCONH₂
5️⃣6️⃣ What type of isomerism is NOT exhibited by different pairs of amines?
🟩 A. Functional isomerism
🟪 B. Position isomerism
🟨 C. Cis-trans isomerism
🟥 D. Metamerism
5️⃣7️⃣ An isomer of CH₃CH₂CHO is:
🟩 A. CH₃COCH₃
🟪 B. CH₃COOCH₃
🟨 C. CH₃OCH₃
🟥 D. CH₃NHCH₃
5️⃣8️⃣. Which of the following alkane(s) do not show isomerism?
🟩 A. Methane
🟪 B. Ethane
🟨 C. Propane
🟥 D. All of them
5️⃣9️⃣ Select one which shows cis-trans isomerism:
🟩 A. Cl₂C=CCl₂
🟪 B. CH₂=CH₂
🟨 C. BrCH=CHBr
🟥 D. Br₂C=CBr₂
6️⃣0️⃣ Which of the following compound may exist as cis-trans isomer?
🟩 A. 1-butene
🟪 B. 2-butene
🟨 C. Cyclopropane
🟥 D. Acetone
6️⃣1️⃣ Which type of isomerism is exhibited by Nitroethane?
🟦 A. Positional Isomerism
🟩 B. Tautomerism
🟪 C. Metamerism
🟨 D. None of them
🟦 A. 7
🟩 B. 5
🟪 C. 6
🟨 D. 9
6️⃣3️⃣ How many quaternary hydrogens are possible in alkane?
🟦 A. 1
🟩 B. 2
🟪 C. 3
🟨 D. 0
6️⃣4️⃣ Dimethyl ether and Ethyl alcohol are called:
🟦 A. Cis-Trans Isomers
🟩 B. Functional Group Isomers
🟪 C. Position Isomers
🟨 D. Metamers
6️⃣5️⃣ Which of the following alkanes contains all four types of carbon atoms (primary, secondary, tertiary & quaternary)?
🟦 A. (CH₃)₃CH
🟩 B. (CH₃)₃CHCH₂CH(CH₃)₂
🟪 C. (C₂H₅)₃CH
🟨 D. (CH₃)₄C
6️⃣6️⃣ If a compound has 'n' asymmetric carbon atoms with different terminal groups, the number of stereoisomers is given by the formula:
🟦 A. 2ⁿ🟩 B. (½)ⁿ
🟪 C. 2√n
🟨 D. √2ⁿ
🟦 A. 9
🟩 B. 7
🟪 C. 4
🟨 D. 11
6️⃣8️⃣ Number of primary carbon atoms in the given compound is:
🟦 A. 5
🟩 B. 6
🟪 C. 4
🟨 D. 2
6️⃣9️⃣ Metamerism is shown by:
🟦 A. Carboxylic Acid
🟩 B. Aldehydes
🟪 C. Neither A nor B
🟨 D. Both A and B
7️⃣0️⃣Acetone and Propionaldehyde are called:
🟦 A. Cis-Trans Isomers
🟩 B. Functional Group Isomers
🟪 C. Position Isomers
🟨 D. Metamers
7️⃣1️⃣ Acetic acid and methyl acetate are called:
🟦 A. Metamers
🟩 B. Functional Group Isomers
🟪 C. Position Isomers
🟨 D. Cis-Trans Isomers
7️⃣2️⃣ Which of the following compounds exhibit geometrical isomerism?
🟦 A. 2-methyl-2-butene
🟩 B. 2-pentene
🟪 C. 2-methyl-2-pentene
🟨 D. 1-pentene
7️⃣3️⃣ The type of stereoisomerism exhibited by enantiomers is called:
🟦 A. Optical Isomerism
🟩 B. Conformational Isomerism
🟪 C. Geometrical Isomerism
🟨 D. Chain Isomerism
7️⃣4️⃣ How many stereoisomers are possible for 2,3-dichlorobutane?
🟦 A. 2
🟩 B. 3
🟪 C. 4
🟨 D. 6
7️⃣5️⃣ How many chiral centers are present in 2,3-dichlorobutane?
🟦 A. 1
🟩 B. 2
🟪 C. 3
🟨 D. 4
7️⃣6️⃣ The number of possible geometrical isomers of 2-butene (C₄H₈) is:
🟦 A. 1
🟩 B. 2
🟪 C. 3
🟨 D. 4
7️⃣7️⃣ Which one of the following pairs are called position isomers?
🟦 A. CH₂(OH)CH₂COOH & CH₃CH(OH)COOH
🟩 B. CH₃CH₂CH₂OH & CH₃CH(OH)CH₃
🟪 C. (C₂H₅)₂CO & CH₃COCH₂CH₂CH₃
🟨 D. All the above
7️⃣8️⃣ The structures (CH₃)₃–CBr and CH₃(CH₂)₃Br present:
🟦 A. Chain Isomerism
🟩 B. Position Isomerism
🟪 C. Functional Isomerism
🟨 D. Both (A) and (B)
7️⃣9️⃣ In keto-enol tautomerism of dicarbonyl compounds, the enol form is preferred in contrast to the keto-form, this is due to:
🟦 A. Presence of Methylene Group
🟩 B. Presence of Carbonyl Group on Each Side of –CH₂–
🟪 C. Resonance Stabilization of Enol Form
🟨 D. Rapid Chemical Exchange
8️⃣0️⃣ Which of the following are isomers?
🟦 A. Ethanol and Ethoxy Ethane
🟩 B. Methanol and Methoxy Methane
🟪 C. Propanoic Acid and Ethyl Acetate
🟨 D. Acetic Acid and Methyl Formate
8️⃣1️⃣ Which alkene could exist in cis and trans forms?
🟦 A. 
🟩 B. 
🟪 C. 
🟨 D. 
🟦 A. Only an Acid
🟩 B. Only an Ether
🟪 C. Only an Alcohol
🟨 D. Both Ether and Alcohol
8️⃣3️⃣ Which one of the following pairs are called position isomers?
🟦 A. CH₃CH₂(OH)CH₂COOH & CH₃-CH(OH)COOH
🟩 B. C₂H₅OH & CH₃OH
🟪 C. (C₂H₅)₂CO & CH₃COCH₂CH₃
🟨 D. None of them
8️⃣4️⃣ Alkene show geometrical isomers due to:
🟦 A. Asymmetry
🟩 B. Rotation around a single bond
🟪 C. Resonance
🟨 D. Restricted rotation around a double bond
8️⃣5️⃣ The formula C₃H₆O₂ represents –
🟦 A. Only an Acid
🟩 B. Both an Acid and an Ester
🟪 C. Only an Alcohol
🟨 D. Both Ether and Alcohol
8️⃣6️⃣ Which of the following are isomers?
🟦 A. Ethanol and Ethoxy Ethane
🟩 B. Methanol and Methoxy Methane
🟪 C. Propanoic Acid and Ethyl Acetate
🟨 D. Propionaldehyde and Acetone
8️⃣7️⃣ An organic compound having molecular C₂H₆O can exhibit functional group isomerism. Select the correct isomers:
🟦 A. Methanol and Methoxy Methane
🟩 B. Ethanol and Methoxy Methane
🟪 C. Ethanol and Ethoxy Ethane
🟨 D. Methanol and Ethoxy Ethane
8️⃣8️⃣ Which of the following pairs are structural isomers?
🟩 B. C₂H₆ — Ethane and Ethene
🟪 C. C₃H₆ — Propene and Cyclopropane
🟨 D. Both A and C
8️⃣9️⃣ Which of the following is an example of positional isomerism?
🟦 A. 1-Butanol and 2-Butanol
🟩 B. Butane and Isobutane
🟪 C. Propene and Cyclopropane
🟨 D. None of these
9️⃣0️⃣ Structural isomerism is given by:
🟦 A. Hydrocarbons only
🟩 B. Hydrocarbons and their Derivatives
🟪 C. Derivatives of Hydrocarbons
🟨 D. Only Carbohydrates
9️⃣1️⃣ Which of the following is the important natural sources of organic compounds?
🟦 A. Plants and Coals
🟩 B. Petroleum
🟪 C. Natural Gas
🟨 D. All of them
9️⃣2️⃣ Which of the following is the decaying product of plants?
🟦 A. Coals
🟩 B. Petroleum
🟪 C. Natural Gas
🟨 D. All of them
9️⃣3️⃣ Which of the following is the main component of coal?
🟦 A. Pb
🟩 B. P
🟪 C. C
🟨 D. Na
9️⃣4️⃣ Which one of the following is NOT a component of coal?
🟦 A. N
🟩 B. O or S
🟪 C. H
🟨 D. Si
9️⃣5️⃣ The hardest and the driest form of coal containing 92-98% C and burns without smoke is called:
🟦 A. Anthracite
🟩 B. Sub-bituminous Coal
🟪 C. Bituminous Coal
🟨 D. Lignite
9️⃣6️⃣ Which one of the following is the product of carbonization or destructive distillation of coal?
🟦 A. Coal Tar
🟩 B. Coke (100% Purest C)
🟪 C. Coke-Oven Gas/Coal Gas
🟨 D. All of them
9️⃣7️⃣ Which of the following is a type of coal?
🟦 A. Anthracite
🟩 B. Bituminous Coal
🟪 C. Lignite (Peat)
🟨 D. All of them
9️⃣8️⃣ The first stage in the conversion of vegetable matter into coal is:
🟦 A. Peat
🟩 B. Anthracite Coal
🟪 C. Bituminous Coal
🟨 D. Lignite
9️⃣9️⃣ Which one of the following forms of coal contains 80% C and is used at power generating stations?
🟦 A. Anthracite
🟩 B. Sub-bituminous Coal
🟪 C. Bituminous Coal
🟨 D. Lignite
1️⃣0️⃣0️⃣ The most abundant form of coal and is used as an energy source and carbonization for coke, coal tar, and coke-oven gas is called:
🟦 A. Anthracite
🟩 B. Sub-bituminous Coal
🟪 C. Bituminous Coal
🟨 D. Lignite
💡 ✨ Answers with Explanations ✨
1️⃣ Answer: B. Isomers
Compounds with the same molecular formula but different structural arrangements are called isomers.
2️⃣ Answer: D. All of them
Chain, stereo, and metamerism are all types of isomerism.
3️⃣ Answer: A. Chain isomers
Isomers with different carbon skeletons or chains are known as chain isomers.
4️⃣ Answer: C. Position isomers
Isomers that differ in the position of a functional group or multiple bonds are position isomers.
5️⃣ Answer: C. 25
6️⃣ Answer: D. All of these
7️⃣ Answer: B. 3
8️⃣ Answer: D. Metamers
Metamers are isomers that differ in the alkyl groups attached to the same functional group.
9️⃣ Answer: C. Functional isomers
Isomers that have different functional groups but the same molecular formula are functional isomers.
🔟 Answer: C. Propene
Propylene oxide (C₃H₆O) is isomeric with propene (C₃H₆), as they both have the same molecular formula but different structural arrangements.
1️⃣1️⃣ Answer: C. 4
C₄H₉OH is butyl alcohol, which has four isomeric forms: primary butyl alcohol, secondary butyl alcohol, isobutyl alcohol, and tertiary butyl alcohol.
1️⃣2️⃣ Answer: D. 8
1️⃣3️⃣ Answer: C. Geometrical isomerism
FCH=CHF shows double bonds, and each carbon is attached to two different groups, which allows for cis-trans or geometrical isomerism.
1️⃣4️⃣Answer: D. 4
1️⃣5️⃣ Answer: D. Metamerism
Alkenes can show chain isomerism, position isomerism, and geometrical isomerism, but not metamerism, as it requires a functional group like R−O−R′, which alkenes do not have.
1️⃣6️⃣ Answer: C. Structural isomers
Ethanol (CH₃CH₂ OH) and dimethyl ether (CH₃OCH₃) are structural isomers (constitutional isomers), as they have the same molecular formula but different structural arrangements.
1️⃣7️⃣ Answer: D. Both A and B
Ethers can exhibit both metamerism (due to different alkyl groups on the same oxygen atom) and functional isomerism (due to the functional group being different in position or bonding).
1️⃣8️⃣ Answer: C. Geometrical
BrCH=CHBr has a double bond with different substituents attached to the carbon atoms, allowing it to show geometrical isomerism (cis-trans).
1️⃣9️⃣ Answer: A. Positional isomers
2-chlorobutane and 1-chlorobutane are positional isomers because the chlorine atom is attached to different carbon atoms in each compound.
2️⃣0️⃣ Answer: B. 8
C₅H₁₂ can form 8 different alkyl groups, based on the possible branching patterns of the carbon chain.
2️⃣1️⃣ Answer: A. 3
2️⃣2️⃣ Answer: D. 7
C₅H₁₀O follows the general formula CₙH₂ₙO, and the possible isomers (4 aldehydes and 3 ketones) total 7 aliphatic carbonyl compounds.
2️⃣3️⃣ Answer: B. 3
2️⃣4️⃣ Answer: D. Tautomerism
Tautomerism involves the migration of a proton to give two structural isomers that are in equilibrium, such as keto-enol tautomerism.
2️⃣5️⃣ Answer: D. 7
C₄H₆ can have 7 structural isomers, including various cyclic and acyclic forms.
2️⃣6️⃣ Answer: B. CH₃CH₂OH
Dimethyl ether (CH₃OCH₃) is isomeric with ethanol (CH₃CH₂OH), as they are both ethers and alcohols, respectively.
2️⃣7️⃣ Answer: D. 5
For C₄H₆ (butyne), the cyclic isomers include cyclobutane, methylcyclopropane, and others, totaling 5 cyclic isomers.
2️⃣8️⃣ Answer: C. 4
2️⃣9️⃣ Answer: B. 5
C₆H₁₄ (hexane) has 5 structural isomers: n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, and 2,3-dimethylbutane.
3️⃣0️⃣Answer: A. 7
C₅H₁₀ can form 7 cyclic isomers, including cyclopentane, methylcyclobutane, and other ring-structured compounds.
3️⃣1️⃣Answer: D. All types
C₄H₁₀O can show metamerism (due to ethers), functional isomerism (because it can be alcohol or ether), and position isomerism (depending on the position of the functional group).
3️⃣2️⃣ Answer: C. Ethers
Ethers do not show metamerism because they do not have a polyvalent functional group like esters or ketones. Ethers only exhibit functional isomerism and sometimes position isomerism.
3️⃣3️⃣ Answer: C. (CH₃)₂O
Dimethyl ether (CH₃OCH₃) is an isomer of ethanol (C₂H₅OH) since both have the same molecular formula but different structural formulas.
3️⃣4️⃣ Answer: A. Skeletal
Alkanes only show skeletal (chain) isomerism, where the carbon chain is arranged differently, but the functional group is the same.
3️⃣5️⃣ Answer: C. Both of them
Both ethers and secondary amines can show metamerism, as they can have different alkyl groups attached to the same functional group.
3️⃣6️⃣ Answer: B. Functional isomers
Acetic acid (CH₃COOH) and methyl formate (CH₃OCOH) are functional isomers because they have different functional groups (carboxyl and ester, respectively).
3️⃣7️⃣ Answer: D. Alkene & alkyne
Alkynes and alkenes both follow the molecular formula CₙH₂ₙ₋₂. Example: C₅H₈ for both alkynes (e.g., 1-pentyne) and alkenes (e.g., 1,4-pentadiene).
3️⃣8️⃣ Answer: C. Cis-trans isomerism
Cis-trans isomerism (geometrical isomerism) only occurs in alkenes, where the groups attached to the double-bonded carbons can be arranged differently (cis or trans).
3️⃣9️⃣ Answer: D.
The isobutyl alkyl radical (C₄H₉) contains an isopropyl group at the end of the chain. Option D represents the correct structure.
4️⃣0️⃣ Answer: C. ClCH=CHCl
ClCH=CHCl shows cis-trans isomerism because both carbons involved in the double bond are attached to different substituents (Cl and H), allowing for cis-trans (geometrical) isomerism.
4️⃣1️⃣ Answer: B. Percentage composition
Pentane (C₅H₁₂) and 2-methylbutane (C₅H₁₂) have the same molecular formula, so they have the same percentage composition (same ratio of elements), although they differ in structure.
4️⃣2️⃣ Answer: B. Alkenes
Geometrical isomerism (cis-trans) occurs in alkenes because the double bond restricts rotation, and different groups can be attached to each carbon of the double bond.
4️⃣3️⃣ Answer: D. None of them
Propene (C₃H₆) cannot exhibit cis-trans isomerism because it only has one methyl group attached to one of the carbons in the double bond, making it impossible to form isomers.
4️⃣4️⃣ Answer: A. Aniline
Aniline (C₆H₅NH₂) is an aromatic compound because it contains a benzene ring. Cyclobutane and cyclohexanol are non-aromatic, and neopentane is aliphatic.
4️⃣5️⃣ Answer: C. Enantiomer
Enantiomers are non-superimposable mirror images of each other, which is the definition of optical isomerism. They occur when a molecule has a chiral center (as in most amino acids, except glycine).
4️⃣6️⃣ Answer: D. 1-pentene
1-Pentene (C₅H₁₀) does not show cis-trans isomerism because the double bond is at the end of the chain (terminal), so no different groups can be attached to both carbons of the double bond.
4️⃣7️⃣ Answer: A. Metamerism
Ethoxyethane (CH₃CH₂OCH₂CH₃) and methoxylpropane (CH₃OCH₂CH₂CH₃) are metamers because they have different alkyl groups attached to the same oxygen atom, a key characteristic of metamerism.
4️⃣8️⃣ Answer: A. Structural isomers
Ethanol (C₂H₅OH) and dimethyl ether (CH₃OCH₃) are structural isomers because they have the same molecular formula but different connectivity of atoms.
4️⃣9️⃣Answer: B. Two
5️⃣0️⃣ Answer: B. Two
Butene (C₄H₈) has two positional isomers: but-1-ene and but-2-ene, which differ in the position of the double bond.
5️⃣1️⃣ Answer: D. All of them
Metamerism occurs in compounds with polyvalent functional groups such as ethers, secondary amides, secondary amines, thioethers, etc. These groups can show isomerism based on the alkyl groups attached to the functional group.
5️⃣2️⃣ Answer: D. Acid halides
Acid halides have a monovalent terminal functional group (-COX), which cannot show metamerism as it does not have multiple alkyl groups attached to the same atom or group.
5️⃣3️⃣ Answer: C. 2-Butene
Geometric (cis-trans) isomerism is possible in alkenes like 2-butene, where different groups can be attached to the carbons in the double bond.
5️⃣4️⃣ Answer: C. But-2-ene
But-2-ene is an alkene, and alkynes like but-1-yne and but-2-yne do not exhibit isomerism with alkenes. Methylcyclopropene and but-1,3-diene are functional and positional isomers of but-1-yne.
5️⃣5️⃣ Answer: A. RNO
An oxime has the general formula R₂C=NOH and exhibits tautomerism. The correct isomer of an oxime would be a structure like RNO, where the nitrogen is doubly bonded to carbon.
5️⃣6️⃣ Answer: C. Cis-trans isomerism
Amines cannot exhibit cis-trans isomerism because they lack the necessary structure—namely, a rigid double bond or cyclic structure that would restrict rotation and allow for different spatial arrangements.
5️⃣7️⃣ Answer: A. CH₃COCH₃
CH₃COCH₃ (acetone) is a functional isomer of CH₃CH₂CHO (ethanal). Both are carbonyl compounds, but one is an aldehyde (ethanal) and the other is a ketone (acetone).
5️⃣8️⃣ Answer: D. All of them
Methane, ethane, and propane do not show isomerism. Isomerism begins with four-carbon alkanes (butane) and above, where chain and positional isomerism can occur.
5️⃣9️⃣ Answer: C. BrCH=CHBr
BrCH=CHBr shows cis-trans isomerism because the double bond in the molecule has two different groups attached to each carbon, fulfilling the conditions for geometrical isomerism.
6️⃣0️⃣ Answer: B. 2-butene
2-butene can exhibit cis-trans isomerism, where the methyl groups can either be on the same side (cis) or opposite sides (trans) of the double bond. 1-butene cannot because it is a terminal alkene.
6️⃣1️⃣ Answer: 🟩 B. Tautomerism
Explanation: Nitroethane exhibits aci-nitro tautomerism where the α−H atom is labile, forming nitrolic acid.
6️⃣2️⃣ Answer: 🟨 D. 9
Explanation: Nine isomers of C₇H₁₆ (Heptane) exist, including straight chain, branched, and methylated forms.
6️⃣3️⃣ Answer: 🟨 D. 0
Explanation: Quaternary carbon atoms are not possible in simple alkanes with fewer than five carbon atoms.
6️⃣4️⃣ Answer: 🟩 B. Functional Group Isomers
Explanation: Dimethyl ether and ethyl alcohol are functional group isomers because they have different functional groups (ether vs alcohol).
6️⃣5️⃣ Answer: 🟩 B.
Explanation: The compound (CH₃)₃CHCH₂CH(CH₃)₂ contains primary, secondary, tertiary, and quaternary carbon atoms.
6️⃣6️⃣ Answer: 🟦 A. 2ⁿ
Explanation: The number of stereoisomers is given by 2ⁿ, where 'n' is the number of asymmetric carbon atoms.
6️⃣7️⃣ Answer: 🟨 D. 11
Explanation: The C₄H₆ formula has 11 isomers, combining dienes, alkynes, and cyclic structures.
6️⃣8️⃣ Answer: 🟩 B. 6
Explanation: The given compound has six primary carbon atoms, each at the ends of carbon chains.
6️⃣9️⃣ Answer: 🟨 C. Neither A nor B
Explanation: Metamerism is not shown by carboxylic acids or aldehydes because they have monovalent terminal functional groups.
7️⃣0️⃣ Answer: 🟩 B. Functional Group Isomers
Explanation: Acetone (ketone) and propionaldehyde (aldehyde) are functional group isomers because they contain different functional groups.
7️⃣1️⃣ Answer: 🟩 B. Functional Group Isomers
Explanation: Acetic acid and methyl acetate are functional group isomers because they contain different functional groups (carboxyl vs ester).
7️⃣2️⃣ Answer: 🟩 B. 2-pentene
Explanation: 2-pentene exhibits geometrical isomerism due to the possibility of cis and trans forms.
7️⃣3️⃣ Answer: 🟦 A. Optical Isomerism
Explanation: Enantiomers are optical isomers because they are non-superimposable mirror images and rotate plane-polarized light in opposite directions.
7️⃣4️⃣ Answer: 🟪 C. 4
Explanation: 2,3-Dichlorobutane has 2 chiral centers, giving 4 stereoisomers (including one meso form).
7️⃣5️⃣ Answer: 🟩 B. 2
Explanation: 2,3-Dichlorobutane has 2 chiral centers (C2 and C3), giving 2 chiral centers in total.
7️⃣6️⃣ Answer: 🟩 B. 2
Explanation: 2-butene has two possible geometrical isomers: cis-2-butene and trans-2-butene.
7️⃣7️⃣ Answer: 🟪 C. (C₂H₅)₂CO & CH₃COCH₂CH₂CH₃
Explanation: These are position isomers because the position of the functional group (carbonyl) is different in each molecule.
7️⃣8️⃣ Answer: 🟦 A. Chain Isomerism
Explanation: (CH₃)₃–CBr and CH₃(CH₂)₃Br exhibit chain isomerism, where the carbon chain differs in structure.
7️⃣9️⃣ Answer: 🟪 C. Resonance Stabilization of Enol Form
Explanation: The enol form is stabilized through resonance, making it more preferred compared to the keto form.
8️⃣0️⃣ Answer: 🟨 D. Acetic Acid and Methyl Formate
Explanation: Acetic acid and methyl formate are functional isomers because they have different functional groups (carboxyl vs ester).
8️⃣1️⃣ Answer: 🟩 B.
Explanation: For geometrical isomerism, the terminal carbons must have different groups. Option B satisfies this condition, while the others do not.
8️⃣2️⃣ Answer: 🟦 A. Only an Acid
Explanation: The molecular formula C₄H₈O₂ corresponds to an acid or ester, specifically an acid in this case.
8️⃣3️⃣ Answer: 🟨 D. None of them
Explanation: The pairs listed are homologues, not position isomers, as they differ by one or more elements but not by functional group position.
8️⃣4️⃣ Answer: 🟨 D. Restricted rotation around a double bond
Explanation: Alkenes exhibit geometrical isomerism due to the restricted rotation around the double bond, preventing cis-trans interconversion.
8️⃣5️⃣ Answer: 🟩 B. Both an Acid and an Ester
Explanation: C₃H6O₂ can represent both an acid (like acetic acid) and an ester (like methyl acetate).
8️⃣6️⃣ Answer: 🟨 D. Propionaldehyde and Acetone
Explanation: Propionaldehyde (RCHO) and acetone (CH₃COCH₃) are functional group isomers, as they contain different functional groups (aldehyde vs ketone).
8️⃣7️⃣ Answer: 🟩 B. Ethanol and Methoxy Methane
Explanation: The molecular formula C₂H6O can represent both an alcohol (ethanol) and an ether (methoxy methane), showing functional group isomerism.
8️⃣8️⃣ Answer: 🟨 D. Both A and C
Explanation: Both Butane (CH₃-CH₂-CH₂-CH₃) and 2-Methylpropane ((CH₃)₃CH), and Propene (CH₃-CH=CH₂) and Cyclopropane (C₃H₆) are structural isomers with different bonding arrangements.
8️⃣9️⃣ Answer: 🟦 A. 1-Butanol and 2-Butanol
Explanation: Position isomerism occurs when the functional group is attached to different positions on the same carbon chain.
9️⃣0️⃣ Answer: 🟩 B. Hydrocarbons and their Derivatives
Explanation: Structural isomerism occurs in hydrocarbons and their derivatives, which can differ by the arrangement of atoms in the molecule.
9️⃣1️⃣ Answer: 🟨 D. All of them
Explanation: The natural sources of organic compounds include plants, animals, coal, petroleum, and natural gas.
9️⃣2️⃣ Answer: 🟨 D. All of them
Explanation: Coals, petroleum, and natural gas are all decaying products of plant matter over millions of years.
9️⃣3️⃣ Answer: 🟪 C. C
Explanation: The main component of coal is carbon (C), which is present in varying amounts depending on the type of coal.
9️⃣4️⃣ Answer: 🟨 D. Si
Explanation: Si (Silicon) is not a typical component of organic compounds or coal. Coal mainly contains carbon, hydrogen, oxygen, nitrogen, and sulfur.
9️⃣5️⃣ Answer: 🟦 A. Anthracite
Explanation: Anthracite is the hardest and driest form of coal, with a carbon content of 92-98%, and it burns without smoke.
9️⃣6️⃣ Answer: 🟨 D. All of them
Explanation: Destructive distillation (carbonization) of bituminous coal produces coke, coal gas, coal tar, and ammonia liquor.
9️⃣7️⃣ Answer: 🟨 D. All of them
Explanation: There are five stages of coal, with different types, including Anthracite, Bituminous coal, and Lignite (Peat).
9️⃣8️⃣ Answer: 🟦 A. Peat
Explanation: Peat is the first stage in the conversion of vegetable matter into coal, consisting mainly of partially decomposed plant material.
9️⃣9️⃣ Answer: 🟩 B. Sub-bituminous Coal
Explanation: Sub-bituminous coal contains about 80% carbon and is used at power generation stations.
1️⃣0️⃣0️⃣ Answer: 🟪 C. Bituminous Coal
Explanation: Bituminous coal is the most abundant form of coal and is used as an energy source, as well as for the production of coke, coal tar, and coke-oven gas.
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