2nd Year Chemistry Chapter 4 TestAROMATIC HYDROCARBONS

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

1. When the C-H bond breaks during the restoration of aromaticity, the cleavage is:

   1. Homolytic

   2. Heterolytic

   3. Photolytic

   4. Thermal

2. What conditions are sufficient for the complete addition of halogens to benzene?

   1. Lewis acid catalyst

   2. Polar solvents only

   3. UV light and heat

   4. Room temperature in dark

3. Nitration of benzene introduces which functional group onto the ring?

   1. Methyl group

   2. Hydroxyl group

   3. Nitro group

   4. Sulfonic acid group

4. Which substituent is an ortho-para director but is structurally deactivating?

   1. -OH

   2. -CH₃

   3. -Cl

   4. -NH₂

5. The unstable intermediate formed in the second step is also known as a:

   1. Pi complex

   2. Sigma complex

   3. Delta complex

   4. Alpha complex

6. What happens to the electron delocalisation of the benzene ring during an addition reaction?

   1. It is enhanced

   2. It remains unchanged

   3. It is destroyed

   4. It becomes temporary

7. Delocalisation energy of benzene is also commonly known as:

   1. Bond energy

   2. Hydration energy

   3. Resonance energy

   4. Heat of combustion

8. During the formation of the electrophile in alkylation, the alkyl halide acts as a:

   1. Lewis acid

   2. Lewis base

   3. Catalyst

   4. Solvent

9. What specific dinitrobenzene isomer can form even at a temperature of 50°C?

   1. 1,2-dinitrobenzene

   2. 1,3-dinitrobenzene

   3. 1,4-dinitrobenzene

   4. 1,5-dinitrobenzene

10. Which product is formed as an extremely minor byproduct when an ortho-para director is present?

    1. Ortho product

    2. Meta product

    3. Para product

    4. Dinuclophile product