Question

Addition reactions are undergone by :

• A. Saturated hydrocarbons (alkanes)
• B. Only alkenes
• C. Only alkynes
• D. Both alkenes and alkynes

Hint:

- Unsaturated compounds (Alkenes & Alkynes) \(\to\) Addition reactions.
- Saturated compounds (Alkanes) \(\to\) Substitution reactions.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks which class of hydrocarbons undergoes chemical addition reactions.

Step 2: Key Formula or Approach:
Addition reactions are characteristic of unsaturated chemical species that contain multiple bonds (double or triple carbon-carbon bonds) which can open up to accept new atoms.

Step 3: Detailed Explanation:

• Saturated Hydrocarbons (Alkanes): Contain only carbon-carbon single bonds. They do not have any double or triple bonds to open up for addition. Therefore, they undergo substitution reactions, not addition reactions.

• Alkenes: Contain carbon-carbon double bonds (\(\text{C}=\text{C}\)). The \(\pi\) bond is relatively weak and can be broken to add elements like hydrogen, halogens, or water across the double bond.

• Alkynes: Contain carbon-carbon triple bonds (\(\text{C}\equiv\text{C}\)). They have two \(\pi\) bonds and can undergo addition reactions in two consecutive steps to first form alkenes and then alkanes.

• Since both alkenes and alkynes are unsaturated, they both readily undergo addition reactions.


Step 4: Final Answer:
Addition reactions are undergone by both alkenes and alkynes.