10th class Chemistry, Chapter 21: Organic Chemistry MCQs

1. Choose the correct IUPAC name for the compound CH₂=CH-CH₂-CH₃.

1. (A) But-3-ene
2. (B) But-1-ene ✓
3. (C) But-2-ene
4. (D) Butene

2. Select a branched chain compound.

1. (A) CH₂=CH-CH₂-CH₃
2. (B) CH₂=C(CH₃)-CH₂-CH₃ ✓
3. (C) CH₃-CH=CH-CH₃
4. (D) CH₃-CH=CH-CH₂-CH₃

3. Which is the displayed formula of ethanol?

1. (A) C₂H₅OH
2. (B) CH₃-CH₂-OH
3. (C) H-C-C-OH with H atoms
4. (D) H-C-C-O-H with all H atoms drawn ✓

4. Identify the aldehydic functional group among the following:

1. (A) -C(=O)-OH
2. (B) -OH
3. (C) -C(=O)-
4. (D) -C(=O)-H ✓

5. Select the general formula of alkyne family.

1. (A) CₙH₂ₙ₊₁
2. (B) CₙH₂ₙ
3. (C) CₙH₂ₙ₋₂ ✓
4. (D) CₙH₂ₙ₋₁

6. How many structural isomers will be there for a saturated hydrocarbon having five carbon atoms?

1. (A) 2
2. (B) 3 ✓
3. (C) 4
4. (D) 5

7. Which ester among the following will be called ethyl propanoate?

1. (A) CH₃-C(=O)-OCH₃
2. (B) CH₃-CH₂-C(=O)-OCH₃
3. (C) CH₃-C(=O)-OC₂H₅
4. (D) CH₃-CH₂-C(=O)-OC₂H₅ ✓

8. Which functional group is present in alkenes?

1. (A) No functional group
2. (B) Carbon-carbon triple bond
3. (C) Carbon-carbon double bond ✓
4. (D) Carbon-carbon single bond

9. Organic chemistry is the branch of chemistry which deals with compounds of:

1. (A) only metals
2. (B) carbon and hydrogen and their derivatives ✓
3. (C) only salts
4. (D) only gases

10. Which element is present in almost all organic compounds besides carbon?

1. (A) Neon
2. (B) Hydrogen ✓
3. (C) Helium
4. (D) Gold

11. Oxides, carbonates and hydrogen carbonates of carbon are studied as:

1. (A) alloys
2. (B) polymers
3. (C) inorganic compounds ✓
4. (D) organic compounds

12. Open chain compounds are also called:

1. (A) acyclic compounds ✓
2. (B) heterocyclic compounds
3. (C) aromatic compounds
4. (D) cyclic compounds

13. 2-Methylpropane is a ____ compound.

1. (A) aromatic
2. (B) branched chain ✓
3. (C) straight chain
4. (D) cyclic

14. When the ring contains carbon atoms only, the compounds are called:

1. (A) aliphatic
2. (B) acyclic
3. (C) heterocyclic
4. (D) carbocyclic ✓

15. When the ring contains other atoms along with carbon, the compounds are called:

1. (A) alicyclic
2. (B) aromatic
3. (C) heterocyclic ✓
4. (D) carbocyclic

16. The general formula of saturated alicyclic hydrocarbons is:

1. (A) CₙH₂ₙ ✓
2. (B) CₙH₂ₙ₋₂
3. (C) CₙHₙ
4. (D) CₙH₂ₙ₊₂

17. Which of the following is an alicyclic compound?

1. (A) Ethene
2. (B) Benzene
3. (C) Cyclohexane ✓
4. (D) Butane

18. A benzene ring has six carbon atoms with:

1. (A) three triple bonds
2. (B) six single bonds
3. (C) three alternate double and single bonds ✓
4. (D) six double bonds

19. The structural formula of a compound shows:

1. (A) only its colour
2. (B) only its melting point
3. (C) the arrangement of atoms and bonds in it ✓
4. (D) only its molecular mass

20. Condensed structural formula omits the ____ bonds.

1. (A) double
2. (B) carbon-carbon
3. (C) triple
4. (D) carbon-hydrogen ✓