1. Which of the following hydrocarbons has only single bonds between carbon atoms?
Answer:
Explanation:
Alkanes are saturated hydrocarbons with only single bonds between carbon atoms.
2. Which hydrocarbon is known as acetylene?
Answer:
Explanation:
Ethyne, with a triple bond between carbon atoms, is commonly known as acetylene.
3. What is the general formula for cycloalkanes?
Answer:
Explanation:
Cycloalkanes have two fewer hydrogen atoms than open-chain alkanes, giving them the formula CnH2n.
4. Which of the following is not a hydrocarbon?
Answer:
Explanation:
Ethanol contains an oxygen atom and is an alcohol, not a hydrocarbon.
5. The hydrocarbon group derived from benzene by removal of a hydrogen atom is:
Answer:
Explanation:
The phenyl group is derived from benzene by removing one hydrogen atom.
6. Which among the following exhibits cis-trans isomerism?
Answer:
Explanation:
Cis-trans isomerism is shown by some cycloalkanes due to restricted rotation around the bond.
7. The simplest aromatic hydrocarbon is:
Answer:
Explanation:
Benzene, with its characteristic six-membered ring, is the simplest aromatic hydrocarbon.
8. In which hydrocarbon is the hybridization of carbon sp?
Answer:
Explanation:
In ethyne, the carbon atoms are sp hybridized.
9. Which of the following is a secondary alkyl group?
Answer:
Explanation:
Isopropyl group is a secondary alkyl group as the free valence is on a secondary carbon.
10. Which among the following is not a member of the alkane series?
Answer:
Explanation:
Butyne has a triple bond and is an alkyne, not an alkane.
11. The complete combustion of hydrocarbons produces:
Answer:
Explanation:
Complete combustion of hydrocarbons in the presence of oxygen yields carbon dioxide and water.
12. Which hydrocarbon has a pleasant smell and is used in making mothballs?
Answer:
Explanation:
Naphthalene is used in mothballs due to its characteristic smell.
13. The hydrocarbon with formula C6H14 is:
Answer:
Explanation:
C6H14 represents an alkane with six carbon atoms, hence hexane.
14. Which of the following is the most reactive towards halogenation?
Answer:
Explanation:
Methane readily undergoes halogenation, especially in the presence of sunlight.
15. The hydrocarbon with both double and triple bonds is called:
Answer:
Explanation:
Compounds with both double and triple bonds are termed alkadiynes.
16. Friedel-Crafts alkylation is catalyzed by:
Answer:
Explanation:
Friedel-Crafts alkylation is catalyzed by Lewis acids like AlCl3.
17. Which of the following reactions results in the addition of a halogen atom?
Answer:
Explanation:
In halogenation, a halogen atom is added to the hydrocarbon.
18. A hydrocarbon with five carbon atoms and a triple bond is:
Answer:
Explanation:
A hydrocarbon with five carbons and a triple bond is pentyne.
19. The bond angle in ethyne is:
Answer:
Explanation:
Due to sp hybridization in ethyne, the bond angle is 180°.
20. Which of the following is an unsaturated hydrocarbon?
Answer:
Explanation:
Butene contains a double bond and is an unsaturated hydrocarbon.