Q.1 Which of the following is a saturated hydrocarbon?
Ethene
Ethane
Ethyne
Benzene
Explanation - Ethane (C2H6) contains only single bonds between carbon atoms, making it a saturated hydrocarbon.
Correct answer is: Ethane
Q.2 Which functional group is present in alcohols?
-COOH
-OH
-CHO
-NH2
Explanation - Alcohols contain the hydroxyl (-OH) functional group attached to a carbon atom.
Correct answer is: -OH
Q.3 Which type of isomerism is shown by C2H5OH and CH3OCH3?
Geometrical isomerism
Chain isomerism
Functional isomerism
Position isomerism
Explanation - C2H5OH (ethanol) and CH3OCH3 (dimethyl ether) have the same molecular formula but different functional groups, exhibiting functional isomerism.
Correct answer is: Functional isomerism
Q.4 Which of the following is an example of an aromatic compound?
Cyclohexane
Benzene
Butane
Propene
Explanation - Benzene has a conjugated ring system with delocalized π-electrons, making it an aromatic compound.
Correct answer is: Benzene
Q.5 Which reagent is commonly used for the bromination of alkenes?
Br2 in CCl4
HBr
NaCl
KMnO4
Explanation - Bromine in carbon tetrachloride (Br2/CCl4) reacts with alkenes in an addition reaction to give dibromo compounds.
Correct answer is: Br2 in CCl4
Q.6 Which of the following statements is true about alkanes?
They contain at least one double bond
They are unsaturated hydrocarbons
They are generally less reactive
They undergo addition reactions easily
Explanation - Alkanes are saturated hydrocarbons and are relatively less reactive due to the absence of π-bonds.
Correct answer is: They are generally less reactive
Q.7 Which type of hybridization is found in alkenes?
sp
sp2
sp3
sp3d
Explanation - In alkenes, the carbon atoms involved in the double bond are sp2 hybridized.
Correct answer is: sp2
Q.8 Markovnikov's rule is used to predict:
The product in free radical reactions
The product in nucleophilic substitution
The regioselectivity in addition reactions of HX to alkenes
The rate of reaction
Explanation - Markovnikov's rule states that in HX addition to an unsymmetrical alkene, the hydrogen attaches to the carbon with more hydrogens.
Correct answer is: The regioselectivity in addition reactions of HX to alkenes
Q.9 Which of the following is a primary alcohol?
CH3CH2OH
CH3OH
CH3CH(OH)CH3
C6H5OH
Explanation - CH3CH2OH (ethanol) has the -OH group attached to a carbon which is connected to only one other carbon, making it a primary alcohol.
Correct answer is: CH3CH2OH
Q.10 Which type of reaction involves the removal of H and OH from adjacent carbons to form a double bond?
Substitution
Addition
Elimination
Oxidation
Explanation - Elimination reactions remove elements (like H and OH) from adjacent carbons, forming a double bond (alkene).
Correct answer is: Elimination
Q.11 What is the IUPAC name of CH3-CH2-CH2-CH3?
Butane
Propane
Pentane
Methane
Explanation - CH3-CH2-CH2-CH3 is a straight-chain alkane with four carbon atoms, named butane.
Correct answer is: Butane
Q.12 Which of the following is not a characteristic of aldehydes?
They contain the -CHO group
They can be oxidized to carboxylic acids
They are highly basic
They undergo nucleophilic addition reactions
Explanation - Aldehydes are generally neutral or slightly polar compounds; they are not highly basic.
Correct answer is: They are highly basic
Q.13 Which compound shows geometrical isomerism?
CH3-CH3
CH2=CHCl
CH3-CHCl-CH3
CH3OH
Explanation - CH3-CHCl-CH3 (2-chloropropene) can show cis-trans (geometrical) isomerism due to restricted rotation around a double bond or ring.
Correct answer is: CH3-CHCl-CH3
Q.14 Which of the following is an example of a tertiary carbon?
CH3-CH2-CH3
(CH3)3C-CH3
CH3CH2CH2OH
CH4
Explanation - A tertiary carbon is attached to three other carbons. In (CH3)3C-CH3, the central carbon is tertiary.
Correct answer is: (CH3)3C-CH3
Q.15 Which reagent is used in the oxidation of primary alcohols to aldehydes?
KMnO4
PCC
NaBH4
LiAlH4
Explanation - Pyridinium chlorochromate (PCC) oxidizes primary alcohols to aldehydes without further oxidation to carboxylic acids.
Correct answer is: PCC
Q.16 Which of the following is a conjugated diene?
1,3-Butadiene
1,2-Butadiene
1-Butene
Cyclobutane
Explanation - 1,3-Butadiene has alternating double and single bonds, making it a conjugated diene.
Correct answer is: 1,3-Butadiene
Q.17 Which of the following statements about free radical halogenation is correct?
It follows Markovnikov's rule
It occurs via a chain mechanism
It requires acidic conditions
It only works with alkenes
Explanation - Free radical halogenation occurs via a chain mechanism involving initiation, propagation, and termination steps.
Correct answer is: It occurs via a chain mechanism
Q.18 Which of the following is the major product in the reaction of CH3CH=CH2 with HBr?
CH3CHBrCH3
CH3CH2CH2Br
CH2BrCH=CH2
CH3CBr=CH2
Explanation - According to Markovnikov's rule, H attaches to the carbon with more H atoms; thus CH3CH2CH2Br is formed.
Correct answer is: CH3CH2CH2Br
Q.19 Which of the following represents a primary amine?
CH3NH2
(CH3)2NH
(CH3)3N
NH3
Explanation - CH3NH2 is a primary amine because the nitrogen is attached to only one alkyl group.
Correct answer is: CH3NH2
Q.20 Which of the following is true for carboxylic acids?
They are basic in nature
They react with alcohols to form esters
They cannot undergo substitution reactions
They have -OH attached to an alkane carbon
Explanation - Carboxylic acids react with alcohols in the presence of acid to form esters (esterification).
Correct answer is: They react with alcohols to form esters
Q.21 Which of the following statements is true for nucleophiles?
They are electron-rich species
They are electron-deficient species
They always donate protons
They are always neutral molecules
Explanation - Nucleophiles have lone pairs of electrons or π-electrons and are attracted to electron-deficient centers.
Correct answer is: They are electron-rich species
Q.22 Which of the following compounds can exhibit tautomerism?
Ketones
Alkanes
Alkenes
Alkynes
Explanation - Ketones can undergo keto-enol tautomerism due to the migration of a proton and shift of a double bond.
Correct answer is: Ketones
Q.23 Which of the following is the correct general formula for alkanes?
CnH2n+2
CnH2n
CnH2n-2
CnH2n+1OH
Explanation - Alkanes are saturated hydrocarbons with the general formula CnH2n+2.
Correct answer is: CnH2n+2
Q.24 Which of the following undergoes SN1 reactions more easily?
Primary alkyl halide
Secondary alkyl halide
Tertiary alkyl halide
Methyl halide
Explanation - Tertiary alkyl halides form more stable carbocations and hence undergo SN1 reactions faster.
Correct answer is: Tertiary alkyl halide