Hydrocarbons Chapter-Wise Test 1

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which substituent on a benzene ring deactivates it and directs to the meta position?

The \( -\ce{CHO} \) (aldehyde) group withdraws electrons, deactivating the ring and directing electrophiles to the meta position.

\( -\ce{CH3} \)
\( -\ce{OH} \)
\( -\ce{CHO} \)
\( -\ce{NH2} \)
3

Which of the following is a characteristic of aromatic hydrocarbons?

Aromatic hydrocarbons, like benzene, have a planar ring structure with delocalized π electrons, contributing to their stability.

Linear chain
Delocalized π electrons
Only single bonds
High reactivity with water
2

Which substituent on a benzene ring increases reactivity towards electrophilic substitution the most?

The \( -\ce{NH2} \) group, a strong electron donor via resonance, increases reactivity towards electrophilic substitution the most.

\( -\ce{Cl} \)
\( -\ce{CH3} \)
\( -\ce{NH2} \)
\( -\ce{NO2} \)
3

Which of the following hydrocarbons burns with a sooty flame?

Benzene (\( \ce{C6H6} \)), an aromatic hydrocarbon, burns with a sooty flame due to its high carbon content and incomplete combustion.

Methane
Ethane
Benzene
Propane
3

Which hydrocarbon with 9 carbon atoms has the maximum possible branching and the lowest boiling point among its isomers?

For \( \ce{C9H20} \), 2,2,3,3-tetramethylpentane has four methyl branches, the most compact structure, lowering its boiling point the most.

Nonane
2-Methylnonane
2,2-Dimethylheptane
2,2,3,3-Tetramethylpentane
4

Which of the following hydrocarbons is saturated?

Saturated hydrocarbons contain only single bonds. Among the options, \( \ce{CH3CH2CH3} \) (propane) is an alkane with only single bonds, making it saturated.

\( \ce{CH3CH2CH3} \)
\( \ce{CH2=CH2} \)
\( \ce{HC#CH} \)
\( \ce{C6H6} \)
1

What is the IUPAC name of \( \ce{CH3CH2CH2CH2CH(CH3)2} \)?

The longest chain has 6 carbons (hexane), with two methyl groups on the fifth carbon, making it 2,2-dimethylhexane.

2,2-Dimethylhexane
3-Methylhexane
Heptane
2-Methylhexane
1

Which of the following hydrocarbons is obtained from coal tar?

Coal tar, a byproduct of coal processing, contains aromatic hydrocarbons like benzene (\( \ce{C6H6} \)).

Benzene
Methane
Ethane
Propane
1

Which gas is commonly found in coal mines?

Methane (\( \ce{CH4} \)), the simplest alkane, is a gas found in coal mines and marshy areas.

Ethane
Methane
Propane
Butane
2

Which hydrocarbon is the main component of CNG?

Compressed natural gas (CNG) primarily consists of methane (\( \ce{CH4} \)), a simple alkane.

Propane
Butane
Methane
Pentane
3

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