Free Isomerism MCQs with Answers

• A. isotopes
• B. isomers
• C. homologues
• D. allotropes

Explanation: Isomers share the molecular formula but differ in how the atoms are connected or arranged in space, so they are genuinely different…

• A. chain isomers
• B. functional group isomers
• C. position isomers
• D. geometric isomers

Explanation: The carbon skeleton and the functional group are the same in both, and only the position of the hydroxyl group along the chain differs…

• A. position isomers
• B. chain isomers
• C. optical isomers
• D. functional group isomers

Explanation: Ethanol contains a hydroxyl group while dimethyl ether contains an oxygen bridging two carbons, so the functional group itself differs and…

• A. the double bond prevents free rotation, fixing the groups on either side
• B. the molecule contains a chiral carbon
• C. the double bond rotates freely
• D. alkenes contain a ring

Explanation: The pi bond locks the two carbons in a fixed relative orientation, so substituents are held either on the same side, cis, or on opposite…

• A. two identical groups and two different ones
• B. four different atoms or groups
• C. at least one double bond
• D. three hydrogen atoms

Explanation: A carbon with four different substituents has no plane of symmetry, so its mirror image cannot be superimposed on it and the two forms are…

• A. one
• B. two
• C. three
• D. four

Explanation: Butane has an unbranched chain of four carbons and 2-methylpropane has a three carbon chain with a methyl branch, and no other arrangement…

• A. Propan-1-ol and propan-2-ol
• B. Butane and 2-methylpropane
• C. Propanal and propanone
• D. Ethane and propane

Explanation: Propanal is an aldehyde and propanone a ketone, yet both have the molecular formula C3H6O, so they differ in functional group.

• A. CH3CH2OH
• B. CH3CHClCH2CH3
• C. CH3CH2CH3
• D. CH2Cl2

Explanation: In CH3CHClCH2CH3 the second carbon carries a methyl group, a chlorine, a hydrogen and an ethyl group, four different substituents, so it…

• A. chain Isomerism
• B. Functional Group Isomerism
• C. Metamerism
• D. Position Isomerism

Explanation: Aldehydes and ketones can have the same molecular formula but different functional groups, such as propanal and propanone, so they show…

• A. 2
• B. 4
• C. 7
• D. 16

Explanation: An aldohexose has four chiral carbon atoms, so the number of possible stereoisomeric aldoses is 2^4 = 16.

• A. aldehydes
• B. ketones
• C. alcohols
• D. carboxylic acid

Explanation: Ethers and alcohols can have the same molecular formula but different functional groups, so they show functional-group isomerism.

• A. metamerism
• B. functional group isomerism
• C. geometric isomerism
• D. position isomerism

Explanation: 1-propanol and 2-propanol have the same molecular formula and the same alcohol functional group, but the OH group is attached at different…

• A. Boiling point
• B. Melting point
• C. Percentage composition
• D. Structural formula

Explanation: Pentane and 2-methylbutane are structural isomers with the same molecular formula, C5H12, so they have the same elemental percentage…

• A. cis-trans isomerism
• B. geometric isomerism
• C. both a & b
• D. none of the above

Explanation: Propene has the structure CH3-CH=CH2; the terminal double-bonded carbon has two identical hydrogen atoms, so cis-trans or geometric…

• A. one
• B. two
• C. three
• D. four

Explanation: C5H12 has three structural isomers: n-pentane, 2-methylbutane and 2,2-dimethylpropane.

• A. polymer
• B. monomer
• C. isomer
• D. allotropes

Explanation: Isomers have the same molecular formula but different arrangements of atoms or different spatial arrangements.

• A. Alkanes
• B. Alkenes
• C. Alkynes
• D. Esters

Explanation: Geometric isomerism is common in alkenes because the pi bond prevents free rotation and each double-bonded carbon may carry two different…

• A. 2
• B. 3
• C. 4
• D. 5

Explanation: The formula C4H9Cl has four structural isomers: 1-chlorobutane, 2-chlorobutane, 1-chloro-2-methylpropane and 2-chloro-2-methylpropane.

• A. Cis Trans isomers
• B. Chain isomers
• C. Position isomers
• D. Metamers

Explanation: Option A is correct as when the substituent groups are oriented in the same direction, the diastereomer is referred to as cis, whereas…

• A. A
• B. B
• C. C
• D. D

Explanation: This compound is 3-hexene. It shows geometrical iomerism as it contains two different groups attached to the carbons of double bond on…