1. Which of the following is a chemical change?   Boiling of water   Rusting of iron   Freezing of water   Dissolving of salt in water   Hint Half-n-half Clue   2. Which of the following is not an allotrope of carbon   Charcoal   Diamond   Silk   Graphite   Half-n-half Clue   3. The lead of a pencil mainly contains   Plastics   Graphite   Lead   Carbon Black   Half-n-half Clue   4. Solubility of a substance in a solvent usually increases with an increase in temperature.   False   True   5. A substance that absorbs moisture is known as   Hydrophobic   Hydrophilic   Amorphous   Hygroscopic   Half-n-half Clue   6. Which of the following gases is green in color?   Chlorine   Krypton   Hydrogen   Neon   Half-n-half Clue   7. Heat is liberated in   Endothermic Reactions   Substitution Reactions   Exothermic Reactions   All chemical reactions   Half-n-half Clue