Class 11 Chemistry MCQ – Organic Chemistry Basic Principles and Techniques

1. Which of the following is the functional group for alcohols?

a) -CHO
b) -COOH
c) -OH
d) -NH2

Answer:

c) -OH

Explanation:

The functional group for alcohols is hydroxyl (-OH).

2. Which of the following organic compounds has a triple bond?

a) Alkene
b) Alkyne
c) Alkane
d) Arene

Answer:

b) Alkyne

Explanation:

Alkynes contain a carbon-carbon triple bond.

3. The IUPAC name of CH3-CH2-OH is:

a) Methanol
b) Ethanol
c) Propanol
d) Methanamine

Answer:

b) Ethanol

Explanation:

According to IUPAC nomenclature, the compound is named as Ethanol.

4. Which process is used to separate a mixture of two miscible liquids?

a) Filtration
b) Crystallization
c) Sublimation
d) Distillation

Answer:

d) Distillation

Explanation:

Distillation is used to separate miscible liquids based on their boiling points.

5. The hybridization of carbon in methane is:

a) sp
b) sp2
c) sp3
d) d2sp3

Answer:

c) sp3

Explanation:

In methane (CH4), carbon undergoes sp3 hybridization.

6. Which among the following is an unsaturated hydrocarbon?

a) Ethane
b) Ethene
c) Methane
d) Propane

Answer:

b) Ethene

Explanation:

Ethene has a double bond and is thus an unsaturated hydrocarbon.

7. The general formula for alkanes is:

a) CnH2n
b) CnH2n+2
c) CnH2n-2
d) CnH2n+1OH

Answer:

b) CnH2n+2

Explanation:

Alkanes follow the general formula CnH2n+2.

8. The organic reaction in which two molecules combine to form a larger molecule with the elimination of a smaller molecule is:

a) Hydrolysis
b) Elimination
c) Substitution
d) Condensation

Answer:

d) Condensation

Explanation:

In condensation, two molecules combine and a smaller molecule, often water, is eliminated.

9. The primary structure of an organic compound represents:

a) Sequence of carbon atoms
b) Arrangement of atoms in space
c) Molecular formula
d) Sequence of functional groups

Answer:

a) Sequence of carbon atoms

Explanation:

The primary structure depicts the sequence in which carbon atoms are arranged in a molecule.

10. Which isomerism is shown by compounds having the same molecular formula but different structures?

a) Geometrical isomerism
b) Optical isomerism
c) Tautomeric isomerism
d) Structural isomerism

Answer:

d) Structural isomerism

Explanation:

Structural isomers have the same molecular formula but different structural formulas.

11. The process of converting alkanes to alkenes involves:

a) Addition
b) Substitution
c) Dehydrogenation
d) Hydrogenation

Answer:

c) Dehydrogenation

Explanation:

Removing hydrogen from alkanes results in alkenes, which is termed dehydrogenation.

12. Which organic compound is also known as wood spirit?

a) Methane
b) Methanol
c) Ethanol
d) Formaldehyde

Answer:

b) Methanol

Explanation:

Methanol is commonly referred to as wood spirit.

13. An aromatic compound contains:

a) Single bonds only
b) Double bonds only
c) Alternating single and double bonds
d) Triple bonds only

Answer:

c) Alternating single and double bonds

Explanation:

Aromatic compounds have a ring with alternating single and double bonds.

14. The study of interaction between matter and electromagnetic radiation is termed as:

a) Chromatography
b) Spectroscopy
c) Centrifugation
d) Titrations

Answer:

b) Spectroscopy

Explanation:

Spectroscopy studies the interaction of electromagnetic radiation with matter.

15. Which reagent is used to test the presence of a double bond in a compound?

a) Tollen's reagent
b) Bromine water
c) Benedict's solution
d) Lime water

Answer:

b) Bromine water

Explanation:

Bromine water adds across double bonds, leading to its decolorization.

16. A functional group present in aldehydes is:

a) -COOH
b) -OH
c) -CHO
d) -NH2

Answer:

c) -CHO

Explanation:

Aldehydes have a carbonyl group (-CHO) as their functional group.

17. The purification technique based on the difference in the rate of migration of components is:

a) Distillation
b) Chromatography
c) Crystallization
d) Filtration

Answer:

b) Chromatography

Explanation:

Chromatography separates components based on their rate of migration.

18. Organic compounds generally have:

a) High melting and boiling points
b) Low melting and boiling points
c) High melting and low boiling points
d) Low melting and high boiling points

Answer:

b) Low melting and boiling points

Explanation:

Due to weaker van der Waals forces, organic compounds typically have low melting and boiling points.

19. The removal of a molecule of water from an alcohol results in:

a) Ether
b) Alkene
c) Alkyne
d) Ester

Answer:

b) Alkene

Explanation:

Dehydration of an alcohol generally produces an alkene.

20. Which among the following represents the secondary suffix in IUPAC nomenclature?

a) Meth-
b) -ane
c) -ol
d) Hydroxy-

Answer:

c) -ol

Explanation:

The secondary suffix indicates the main functional group. In this case, '-ol' indicates an alcohol.

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