Organic Chemistry – Some Basic Principles and Techniques Chapter-Wise Test 8

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which compound with \( \ce{C5H8} \) has a degree of unsaturation of 2 and contains a triple bond?

Degree of unsaturation = \( \frac{2C + 2 - H}{2} = \frac{12 - 8}{2} = 2 \). \( \ce{CH3CH2C#CCH3} \) (pent-2-yne) has one triple bond (2 units), fitting \( \ce{C5H8} \).

\( \ce{CH2=CHCH=CHCH3} \)
\( \ce{CH3CH=CHCH=CH2} \)
\( \ce{CH3C(CH3)=CHCH3} \)
\( \ce{CH3CH2C#CCH3} \)
4

A compound with 10 \( \sigma \) bonds and 1 \( \pi \) bond has a molecular formula of \( \ce{C4H8} \). Which carbon has a bond angle of approximately 120°?

\( \ce{CH3CH=CHCH3} \) fits \( \ce{C4H8} \) with 10 \( \sigma \) (7 C-H, 2 C-C, 1 from C=C) and 1 \( \pi \) (C=C). The second carbon (\( \ce{CH=} \)) is \( sp^2 \), with a 120° bond angle.

First carbon
Fourth carbon
Second carbon
Third carbon
3

Which carbon in \( \ce{CH3CH2C(=O)NH2} \) has the highest electronegativity due to hybridization?

In \( \ce{CH3CH2C(=O)NH2} \) (propanamide), the carbonyl carbon (\( \ce{C=O} \)) is \( sp^2 \) hybridized (33% s-character), higher than \( sp^3 \) (25%) of other carbons, making it the most electronegative.

Carbonyl carbon
Carbon in \( \ce{CH3} \)
Carbon in \( \ce{CH2} \)
Nitrogen-attached carbon
1

In the estimation of carbon and hydrogen, 0.25 g of a compound gave 0.66 g of \( \ce{CO2} \) and 0.135 g of \( \ce{H2O} \). What is the empirical formula?

Mass of C = \( \frac{12}{44} \times 0.66 = 0.18 \) g. Mass of H = \( \frac{2}{18} \times 0.135 = 0.015 \) g. Ratio C:H = \( \frac{0.18/12}{0.015/1} = 1:1 \). Empirical formula = \( \ce{CH} \).

\( \ce{CH2} \)
\( \ce{C2H5} \)
\( \ce{CH3} \)
\( \ce{CH} \)
4

In the Dumas method, 0.25 g of a compound gave 50 mL of \( \ce{N2} \) at STP. What is the percentage of nitrogen?

Mass of N = \( \frac{28}{22400} \times 50 = 0.0625 \) g. Percentage = \( \frac{0.0625}{0.25} \times 100 = 25\% \).

22%
23%
24%
25%
4

In the estimation of carbon and hydrogen, water is absorbed by which substance?

In the Liebig method, \( \ce{H2O} \) produced from hydrogen is absorbed by anhydrous \( \ce{CaCl2} \) (calcium chloride).

\( \ce{CuSO4} \)
\( \ce{CaCl2} \)
\( \ce{KOH} \)
\( \ce{AgNO3} \)
2

What is the IUPAC name of \( \ce{CH3CH(CH3)CH2CH2OH} \)?

The compound has a 4-carbon chain with a methyl group on the second carbon and an -OH on the first, named 3-methylbutan-1-ol.

3-Methylbutan-1-ol
2-Methylbutan-1-ol
Pentan-1-ol
3-Methylpentan-1-ol
1

In the Carius method, a compound weighing 0.24 g produces 0.47 g of \( \ce{AgCl} \) and 0.233 g of \( \ce{BaSO4} \). What is the ratio of chlorine to sulphur by mass?

Mass of Cl = \( \frac{35.5}{143.5} \times 0.47 \approx 0.116 \) g. Mass of S = \( \frac{32}{233} \times 0.233 \approx 0.032 \) g. Ratio = \( \frac{0.116}{0.032} \approx 3.625:1 \), which rounds to 4:1 for practical purposes.

3:1
4:1
5:1
2:1
2

Which of the following compounds has the highest number of \( \sigma \) bonds?

\( \ce{CH3CH2CH2CH3} \) (butane) has 13 \( \sigma \) bonds (10 C-H, 3 C-C), more than the others: \( \ce{CH4} \) (4), \( \ce{CH2=CH2} \) (5), \( \ce{HC#CH} \) (3).

\( \ce{CH4} \)
\( \ce{CH2=CH2} \)
\( \ce{CH3CH2CH2CH3} \)
\( \ce{HC#CH} \)
3

In paper chromatography, the separation of components depends on the difference in their:

Paper chromatography (a type of partition chromatography) separates based on the partition coefficient between the stationary water phase and mobile solvent phase.

Boiling points
Adsorption strength
Molecular weights
Partition coefficients
4

Performance Summary

Score:

Category Details
Total Attempts:
Total Skipped:
Total Wrong Answers:
Total Correct Answers:
Time Taken:
Average Time Taken per Question:
Accuracy:
0