Hydrocarbons Chapter-Wise Test 6

Correct answer Carries: 4.

Wrong Answer Carries: -1.

How many hydrogen atoms are bonded to the carbon atom in \( \ce{CH3CH2CH(CH3)2} \) that bears two methyl groups?

The carbon with two methyl groups (\( \ce{C(CH3)2} \)) is tertiary, bonded to three carbons and one hydrogen.

0
2
1
3
3

Which of the following groups is moderately deactivating but ortho-para directing on a benzene ring?

Halogens like \( -\ce{Cl} \) are moderately deactivating due to their -I effect but direct electrophiles to ortho and para positions due to resonance.

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

What is the effect of branching on the boiling point of alkanes?

Branching reduces the surface area of alkane molecules, decreasing intermolecular forces and thus lowering the boiling point.

Increases
No effect
Fluctuates
Decreases
4

How many isomers are possible for \( \ce{C6H14} \)?

For \( \ce{C6H14} \), a hexane molecule, there are 5 possible structural isomers due to different carbon chain arrangements.

3
4
6
5
4

What is the \( \ce{C-C} \) bond length in alkanes?

In alkanes, the \( \ce{C-C} \) single bond length is 154 pm due to \( sp^3 \) hybridization.

120 pm
134 pm
154 pm
145 pm
3

What is the IUPAC name of \( \ce{CH3CH2CH(CH2CH3)CH3} \)?

The longest chain has 5 carbons (pentane), with an ethyl group on the third carbon, making it 3-ethylpentane.

3-Ethylpentane
2-Methylpentane
Hexane
3-Methylpentane
1

Which hydrocarbon with molecular formula \( \ce{C4H6} \) contains a triple bond?

Butyne (\( \ce{CH3C#CH} \)) is an alkyne with a triple bond, fitting \( \ce{C4H6} \) (\( \ce{C_nH_{2n-2}} \)), unlike butadiene with two double bonds.

Butyne
Butadiene
Cyclobutane
Butene
1

Which hydrocarbon is a starting material for the synthesis of aspirin?

Benzene (\( \ce{C6H6} \)) is used as a starting material in the synthesis of aspirin via intermediates like salicylic acid.

Methane
Ethane
Propane
Benzene
4

Which hydrocarbon is the simplest aromatic compound?

Benzene (\( \ce{C6H6} \)) is the simplest aromatic hydrocarbon with a six-membered ring and delocalized π electrons.

Benzene
Toluene
Methane
Ethane
1

A hydrocarbon with molecular formula \( \ce{C7H16} \) has three methyl branches. What is its IUPAC name?

For \( \ce{C7H16} \) with three methyl branches, the longest chain is 4 carbons (butane), with methyl groups on carbons 2, 2, and 3, named 2,2,3-trimethylbutane.

2,2,3-Trimethylbutane
2,3,3-Trimethylbutane
2,2-Dimethylpentane
3-Methylhexane
1

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