Organic Chemistry – Some Basic Principles and Techniques Chapter-Wise Test 13

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which compound can exhibit position isomerism with \( \ce{CH3CH2CH2OH} \)?

Position isomerism involves the same functional group in different positions. \( \ce{CH3CH(OH)CH3} \) (propan-2-ol) has the -OH group on a different carbon than propan-1-ol.

\( \ce{CH3CH(OH)CH3} \)
\( \ce{CH3OCH3} \)
\( \ce{CH3CH2CHO} \)
\( \ce{CH3CH2CH3} \)
1

Which intermediate is stabilized by the hyperconjugation effect?

Carbocations are stabilized by hyperconjugation, where adjacent C-H bonds donate electron density to the empty p-orbital.

Carbanion
Free radical
Carbene
Carbocation
4

What is the hybridization of the carbon atom in \( \ce{HC#N} \)?

In \( \ce{HC#N} \) (hydrogen cyanide), the carbon forms a triple bond with nitrogen and a single bond with hydrogen, indicating \( sp \) hybridization.

\( sp^3 \)
\( sp^2 \)
\( sp \)
\( sp^3d \)
3

In the Dumas method, 0.5 g of a compound gave 112 mL of \( \ce{N2} \) at STP. What is the percentage of nitrogen?

Mass of N = \( \frac{28}{22400} \times 112 = 0.14 \) g. Percentage = \( \frac{0.14}{0.5} \times 100 = 28\% \).

24%
26%
30%
28%
4

Which compound with the formula \( \ce{C5H10} \) has the highest degree of unsaturation?

Degree of unsaturation = \( \frac{2C + 2 - H}{2} \). For \( \ce{C5H10} \), it’s 1 (e.g., pentene). \( \ce{CH2=CHCH2CH=CH2} \) has 2 double bonds (degree = 2), but fits \( \ce{C5H8} \). Among \( \ce{C5H10} \), all have 1, but cyclic \( \ce{C5H10} \) (cyclopentane) has none, so pent-1-ene is typical.

\( \ce{CH3CH2CH2CH=CH2} \)
\( \ce{CH3CH=CHCH2CH3} \)
\( \ce{CH3C(CH3)=CHCH3} \)
\( \ce{CH2=CHCH2CH=CH2} \)
4

Which carbon in \( \ce{CH3CH2C#CCH2CH3} \) has the smallest bond angle?

In \( \ce{CH3CH2C#CCH2CH3} \) (pent-2-yne), \( sp^3 \) carbons (\( \ce{CH3}, \ce{CH2} \)) have 109.5°, while \( sp \) carbons (\( \ce{C#C} \)) have 180°. The third carbon (\( \ce{C#} \)) has the largest angle, so the first (\( \ce{CH3} \)) has the smallest.

First carbon
Third carbon
Fourth carbon
Fifth carbon
1

The reaction \( \ce{CH3CH2Br + OH^- -> CH3CH2OH + Br^-} \) is an example of which type of reaction?

This is a nucleophilic substitution reaction where \( \ce{OH^-} \) replaces \( \ce{Br^-} \) on the carbon atom.

Elimination
Nucleophilic substitution
Addition
Rearrangement
2

What is the total number of \( \sigma \) and \( \pi \) bonds in \( \ce{CH3C#CH} \)?

In \( \ce{CH3C#CH} \) (propyne), there are 6 \( \sigma \) bonds (3 C-H, 1 C-C, 2 from C≡C) and 2 \( \pi \) bonds (from C≡C). Total = 6 + 2 = 8.

8
7
9
6
1

Which compound can exhibit geometrical isomerism?

Geometrical isomerism requires a double bond with different substituents on each carbon. \( \ce{CH3CH=CHCH2CH3} \) (pent-2-ene) can exist as cis or trans isomers.

\( \ce{CH3CH=CHCH2CH3} \)
\( \ce{CH3CH2CH3} \)
\( \ce{CH3CH2CH2OH} \)
\( \ce{CH3C#CH} \)
1

Which reagent is used in Lassaigne’s test to detect halogens in an organic compound?

Halogens form \( \ce{NaX} \) (X = Cl, Br, I) in Lassaigne’s test, detected by forming a precipitate with silver nitrate (\( \ce{AgNO3} \)).

Sodium nitroprusside
Ferric chloride
Silver nitrate
Lead acetate
3

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