Chemical Properties of Carbon Compounds: Addition MCQs Quiz | Class 10
Class: X | Subject: Science (Code 086) | Unit: Unit I: Chemical Substances – Nature and Behaviour | Covering: Typical of unsaturated hydrocarbons, hydrogenation idea (basic) | Attempt these 10 MCQs to test your understanding, view your score, and download the solution PDF.
Overview: Addition Reactions in Carbon Compounds
Addition reactions are a characteristic property of unsaturated hydrocarbons (alkenes and alkynes). Unlike saturated hydrocarbons which undergo substitution, unsaturated compounds add atoms across their double or triple bonds to form saturated products. This reaction is fundamentally important in both industrial chemistry and biological systems.
Key Concepts
- Nature of Reaction: Occurs only in compounds with double or triple bonds (unsaturated).
- Mechanism: The weaker bond (part of the double/triple bond) breaks, allowing new atoms to attach to the carbon atoms.
- Test for Unsaturation: Bromine water serves as a test. Unsaturated compounds decolorize the orange-brown bromine water, while saturated compounds do not.
Hydrogenation of Oils
One of the most commercially significant addition reactions is the hydrogenation of vegetable oils.
| Property | Vegetable Oils | Animal Fats |
|---|---|---|
| State at Room Temp | Usually Liquid | Usually Solid |
| Carbon Chains | Long unsaturated carbon chains | Saturated carbon chains |
| Health Impact | Healthy (generally) | Harmful (increases cholesterol) |
| Reaction | Undergo addition with Hydrogen | Do not undergo addition |
Process: Vegetable oils are treated with hydrogen in the presence of a catalyst like Nickel (Ni) or Palladium (Pd) to form solid fats (vanaspati ghee). This process turns unsaturated fats into saturated fats.
Quick Revision List
- Reagent: Hydrogen (H2).
- Catalyst: Nickel (Ni) or Palladium (Pd).
- Observation: Liquid oil turns into solid fat.
- General Reaction: Alkene + H2 -> Alkane.
Extra Practice Questions
1. Why are catalysts required in hydrogenation? (To speed up the reaction by lowering activation energy).
2. Can propane undergo addition reactions? (No, it is saturated).
3. Name the industrial product obtained by hydrogenation of vegetable oil. (Vanaspati Ghee/Margarine).
4. What is the color change when ethene reacts with bromine water? (Orange to Colorless).
5. Which is healthier for cooking: unsaturated oils or saturated fats? (Unsaturated oils).
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