Organic Chemistry – Some Basic Principles and Techniques Chapter-Wise Test 15

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which of the following is a characteristic of a homologous series?

Members of a homologous series differ by a \( \ce{-CH2-} \) unit, maintaining the same functional group and general formula.

Same molecular formula
Differ by \( \ce{-CH2-} \) unit
Different functional groups
Same boiling point
2

Which type of bond cleavage produces free radicals?

Homolytic cleavage involves equal splitting of a bond, producing free radicals with unpaired electrons.

Heterolytic
Ionic
Homolytic
Electrophilic
3

In the estimation of hydrogen, 0.2 g of a compound gave 0.09 g of \( \ce{H2O} \). What is the percentage of hydrogen?

Mass of H = \( \frac{2}{18} \times 0.09 = 0.01 \) g. Percentage = \( \frac{0.01}{0.2} \times 100 = 5\% \).

4%
6%
7%
5%
4

In the estimation of sulphur, 0.25 g of a compound gave 0.583 g of \( \ce{BaSO4} \). What is the percentage of sulphur?

Molar mass of \( \ce{BaSO4} = 233 \) g/mol, S = 32 g/mol. Mass of S = \( \frac{32}{233} \times 0.583 = 0.08 \) g. Percentage = \( \frac{0.08}{0.25} \times 100 = 32\% \).

28%
30%
32%
34%
3

Which carbocation is most likely to rearrange to a more stable form if formed from \( \ce{CH3CH2CH2CH2CH2Cl} \) via heterolytic cleavage?

Cleavage at \( \ce{CH2Cl} \) forms \( \ce{CH3CH2CH2CH2CH2+} \) (primary). A hydride shift to \( \ce{CH3CH2CH2CH+CH3} \) (secondary) increases stability via hyperconjugation.

\( \ce{CH3CH2CH2CH2+} \)
\( \ce{CH3CH2+} \)
\( \ce{CH3CH2CH2CH+CH3} \)
\( \ce{CH3C+(CH3)CH2CH3} \)
3

In the Carius method, 0.18 g of a compound gave 0.287 g of \( \ce{AgCl} \). What is the percentage of chlorine?

Molar mass of \( \ce{AgCl} = 143.5 \) g/mol, Cl = 35.5 g/mol. Mass of Cl = \( \frac{35.5}{143.5} \times 0.287 = 0.071 \) g. Percentage = \( \frac{0.071}{0.18} \times 100 = 39.44\% \approx 40\% \).

38%
39%
40%
41%
3

Which species is least likely to act as a nucleophile in a reaction with \( \ce{CH3CH2Cl} \)?

\( \ce{CH3CH2+} \) is a carbocation (electrophile), not a nucleophile, unlike \( \ce{OH^-}, \ce{NH3}, \ce{CN^-} \), which are electron-rich.

\( \ce{OH^-} \)
\( \ce{NH3} \)
\( \ce{CH3CH2+} \)
\( \ce{CN^-} \)
3

In the estimation of sulphur and carbon, 0.2 g of a compound gave 0.466 g of \( \ce{BaSO4} \) and 0.44 g of \( \ce{CO2} \). What is the mass ratio of sulphur to carbon?

Mass of S = \( \frac{32}{233} \times 0.466 = 0.064 \) g. Mass of C = \( \frac{12}{44} \times 0.44 = 0.12 \) g. Ratio = \( \frac{0.064}{0.12} = 0.533 \approx 8:15 \).

1:2
2:3
8:15
3:4
3

Which compound exhibits chain isomerism with \( \ce{CH3CH2CH2CH3} \)?

Chain isomerism involves different carbon skeletons. \( \ce{CH3CH(CH3)CH3} \) (2-methylpropane) has the same molecular formula (\( \ce{C4H10} \)) as n-butane but a branched structure.

\( \ce{CH3CH(CH3)CH3} \)
\( \ce{CH3CH2CH2OH} \)
\( \ce{CH3CH=CH2} \)
\( \ce{CH3CH2CH3} \)
1

Which electrophile is most likely to attack the double bond in \( \ce{CH3CH=CHCH3} \) to form a stable carbocation?

\( \ce{H+} \) adds to \( \ce{CH3CH=CHCH3} \) (but-2-ene), forming \( \ce{CH3CH+CH2CH3} \) (secondary carbocation), stabilized by hyperconjugation, more favorable than other electrophiles here.

\( \ce{Cl+} \)
\( \ce{NO2+} \)
\( \ce{CH3+} \)
\( \ce{H+} \)
4

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