Organic Chemistry – Some Basic Principles and Techniques Chapter-Wise Test 6

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which purification method is least suitable for separating a mixture of two solids with identical melting points but different \( R_f \) values in chromatography?

Crystallization relies on melting point or solubility differences, ineffective here. Chromatography exploits \( R_f \) differences, making it suitable.

Sublimation
Paper chromatography
Column chromatography
Crystallization
4

What is the IUPAC name of \( \ce{(CH3)2CHCH2OH} \)?

The compound has a 3-carbon chain with a methyl branch on the second carbon and an -OH on the first, named 2-methylpropan-1-ol.

2-Methylpropan-1-ol
Butan-1-ol
Propan-2-ol
2-Methylbutan-1-ol
1

In the estimation of hydrogen, 0.24 g of a compound gave 0.108 g of \( \ce{H2O} \). What is the percentage of hydrogen?

Mass of H = \( \frac{2}{18} \times 0.108 = 0.012 \) g. Percentage = \( \frac{0.012}{0.24} \times 100 = 5\% \).

4%
6%
7%
5%
4

Which carbon in \( \ce{CH3C#N} \) has the highest electronegativity?

In \( \ce{CH3C#N} \), the carbon triple-bonded to nitrogen is \( sp \) hybridized (50% s-character), making it the most electronegative.

First carbon
Third carbon
All carbons equally
Second carbon
4

In the Dumas method, 0.32 g of a compound gave 80 mL of \( \ce{N2} \) at STP. What is the percentage of nitrogen?

Mass of N = \( \frac{28}{22400} \times 80 = 0.1 \) g. Percentage = \( \frac{0.1}{0.32} \times 100 = 31.25\% \approx 31\% \).

30%
32%
33%
31%
4

A compound with molecular formula \( \ce{C4H10O} \) is a functional isomer of \( \ce{CH3CH2CH2CH2OH} \) and lacks a hydroxyl group. What is its IUPAC name?

\( \ce{CH3CH2CH2CH2OH} \) (butan-1-ol) is an alcohol. Its functional isomer without -OH is \( \ce{CH3CH2OCH2CH3} \) (diethyl ether), an ether.

Diethyl ether
Butan-2-ol
2-Methylpropan-1-ol
Butanal
1

Which carbon in \( \ce{CH3CH2CH2C(=O)CH3} \) experiences the greatest inductive effect from the oxygen atom?

In \( \ce{CH3CH2CH2C(=O)CH3} \) (pentan-2-one), the carbonyl carbon (\( \ce{C=O} \)) is directly bonded to oxygen, experiencing the strongest -I effect due to proximity.

First carbon
Second carbon
Carbonyl carbon
Carbon in \( \ce{CH3} \) attached to carbonyl
3

Which technique is most suitable for separating a mixture of two solids, one of which is soluble in ethanol and the other insoluble, both with high melting points?

Crystallization uses differential solubility (e.g., ethanol) to dissolve one solid and recrystallize it, leaving the insoluble one behind, ideal when melting points are irrelevant.

Crystallization
Sublimation
Simple distillation
Chromatography
1

Which technique is most suitable for separating a mixture of \( \ce{C6H6} \) (b.p. 80°C) and \( \ce{C7H8} \) (b.p. 110°C)?

Simple distillation is used for liquids with boiling point differences > 25°C, like benzene (80°C) and toluene (110°C).

Fractional distillation
Sublimation
Simple distillation
Chromatography
3

In the estimation of sulphur, sulphur is converted to which compound for precipitation?

In the Carius method, sulphur is oxidized to \( \ce{H2SO4} \), which reacts with \( \ce{BaCl2} \) to form \( \ce{BaSO4} \) for estimation.

\( \ce{Ag2S} \)
\( \ce{BaSO4} \)
\( \ce{Na2S} \)
\( \ce{PbS} \)
2

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