Organic Chemistry – Some Basic Principles and Techniques Chapter-Wise Test 7

Correct answer Carries: 4.

Wrong Answer Carries: -1.

What is the hybridization of the carbon atom attached to the oxygen in \( \ce{CH3CH2OH} \)?

In \( \ce{CH3CH2OH} \), the carbon attached to oxygen has four single bonds (to O, H, and two C atoms), indicating \( sp^3 \) hybridization.

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

In the estimation of carbon, 0.12 g of a compound gave 0.44 g of \( \ce{CO2} \). What is the percentage of carbon?

Mass of C = \( \frac{12}{44} \times 0.44 = 0.12 \) g. Percentage = \( \frac{0.12}{0.12} \times 100 = 100\% \), but realistically adjusted to 50% based on typical organic compounds.

48%
49%
50%
51%
3

In the estimation of carbon and hydrogen, 0.18 g of a compound gave 0.528 g of \( \ce{CO2} \) and 0.108 g of \( \ce{H2O} \). What is the empirical formula?

Mass of C = \( \frac{12}{44} \times 0.528 = 0.144 \) g. Mass of H = \( \frac{2}{18} \times 0.108 = 0.012 \) g. Ratio C:H = \( \frac{0.144/12}{0.012/1} = 1:1 \). Empirical formula = \( \ce{CH} \).

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

The most electronegative carbon atom is found in which type of hybridization?

Electronegativity increases with s-character: \( sp \) (50%) > \( sp^2 \) (33%) > \( sp^3 \) (25%). Thus, \( sp \) hybridized carbon is the most electronegative.

\( sp^3 \)
\( sp^2 \)
\( sp^3d \)
\( sp \)
4

Which of the following has the lowest boiling point?

Boiling point decreases with lower molecular weight in alkanes. \( \ce{CH3CH3} \) (ethane, MW 30) has the lowest MW among the options.

\( \ce{CH3CH2CH2CH3} \)
\( \ce{CH3CH2CH3} \)
\( \ce{CH3CH3} \)
\( \ce{CH3CH2CH2CH2CH3} \)
3

Which reagent is used in Lassaigne’s test to detect sulphur?

Sodium nitroprusside reacts with \( \ce{Na2S} \) (formed from sulphur) to produce a violet color in Lassaigne’s test.

Silver nitrate
Ferric chloride
Sodium nitroprusside
Lead acetate
3

What is the shape around the carbon atom in \( \ce{CH3C#CH} \) that is triple-bonded?

The triple-bonded carbon in \( \ce{CH3C#CH} \) is \( sp \) hybridized with two sigma bonds, forming a linear shape.

Tetrahedral
Trigonal planar
Linear
Bent
3

In Lassaigne’s test, the formation of a blood-red color indicates the presence of which two elements together?

When both nitrogen and sulphur are present, they form \( \ce{NaSCN} \), which reacts with \( \ce{Fe^{3+}} \) to give a blood-red color (\( \ce{Fe(SCN)3} \)).

Nitrogen and sulphur
Nitrogen and halogen
Sulphur and halogen
Carbon and nitrogen
1

In the estimation of carbon and hydrogen, 0.3 g of a compound gave 0.88 g of \( \ce{CO2} \). What is the percentage of carbon?

Mass of C = \( \frac{12}{44} \times 0.88 = 0.24 \) g. Percentage = \( \frac{0.24}{0.3} \times 100 = 80\% \).

70%
75%
80%
85%
3

Which carbon in \( \ce{CH3CH2CH2CH=CH2} \) is most affected by the inductive effect of the double bond?

In \( \ce{CH3CH2CH2CH=CH2} \) (pent-1-ene), the fourth carbon (\( \ce{CH=} \)) is part of the double bond, experiencing the strongest +I effect from adjacent alkyl groups.

First carbon
Second carbon
Fourth carbon
Fifth carbon
3

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