Hydrocarbons Chapter-Wise Test 10

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which hydrocarbon has a density closest to that of water at room temperature?

Decane (\( \ce{C10H22} \)) has a density of ~0.73 g/cm³, closer to water (1 g/cm³) than lighter alkanes like hexane (0.66 g/cm³).

Methane
Hexane
Octane
Decane
4

What is the general formula for alkynes?

Alkynes are unsaturated hydrocarbons with one triple bond, following the general formula \( \ce{C_nH_{2n-2}} \).

\( \ce{C_nH_{2n-2}} \)
\( \ce{C_nH_{2n}} \)
\( \ce{C_nH_{2n+2}} \)
\( \ce{C_nH_n} \)
1

Which of the following hydrocarbons is toxic and carcinogenic?

Polynuclear hydrocarbons like 1,2-benzpyrene, formed from incomplete combustion, are toxic and carcinogenic.

\( \ce{CH4} \)
\( \ce{C3H8} \)
\( \ce{C2H4} \)
1,2-Benzpyrene
4

Which of the following is a property of alkanes?

Alkanes are non-polar due to the small electronegativity difference between carbon and hydrogen, affecting their solubility.

Highly polar
Non-polar
Acidic nature
Basic nature
2

A hydrocarbon with 5 carbon atoms has 10 hydrogen atoms and forms a ring. What is its IUPAC name?

The formula \( \ce{C5H10} \) suggests a cycloalkane (saturated, \( \ce{C_nH_{2n}} \)) with a five-membered ring, named cyclopentane.

Cyclopentane
Pentene
Cyclopentene
Methylcyclobutane
1

Which hydrocarbon with 8 carbon atoms has the lowest melting point among its isomers?

For \( \ce{C8H18} \), 2,2,3,3-tetramethylbutane, with its highly branched structure, has the lowest melting point due to poor packing.

Octane
2,2,3,3-Tetramethylbutane
3-Ethylhexane
2,3-Dimethylhexane
2

A hydrocarbon with 6 carbon atoms and 10 hydrogen atoms has one degree of unsaturation. What is its IUPAC name?

\( \ce{C6H10} \) with one degree of unsaturation suggests a single double bond or ring. Cyclohexene, a six-membered ring with one double bond, fits.

Cyclohexane
Cyclohexene
Hexyne
Benzene
1

Which hydrocarbon is used as a solvent in the pharmaceutical industry?

Toluene (\( \ce{C6H5CH3} \)), an aromatic hydrocarbon, is widely used as a solvent in pharmaceuticals.

Methane
Ethane
Toluene
Propane
3

What is the common name of \( \ce{C6H5CH2CH3} \)?

The compound \( \ce{C6H5CH2CH3} \) is an aromatic hydrocarbon with an ethyl group on a benzene ring, commonly called ethylbenzene.

Toluene
Ethylbenzene
Xylene
Benzene
2

Which hydrocarbon requires the highest amount of oxygen per carbon atom for complete combustion?

Butane (\( \ce{C4H10} \)) requires 13/2 \( \ce{O2} \) for 4 carbons (1.625 \( \ce{O2} \)/C), higher than benzene’s 1.25 \( \ce{O2} \)/C.

\( \ce{C6H6} \)
\( \ce{C5H12} \)
\( \ce{C6H14} \)
\( \ce{C4H10} \)
4

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