1. Which of the following is not a physical change?   Precipitation   Distillation   Oxidation   Decantation   Hint Half-n-half Clue   2. The two allotropes of phosphorus are   Red Phosphorus, Yellow Phosphorus   Rhombic Phosphorus, Monoclinic Phosphorus   Crystalline Phosphorus, Amorphous Phosphorus   Alpha Phosphorus, Beta Phosphorus   Half-n-half Clue   3. Which of the following is not an acid?   HCl   H2SO4   NaOH   HNO3   Half-n-half Clue   4. Catalysts often speed up certain chemical reactions.   False   True   5. Which of the following is a chemical change?   Rusting of iron   Dissolving of salt in water   Boiling of water   Freezing of water   Half-n-half Clue   6. What is the combination of any substance with oxygen known as?   Reduction   Combustion   Hydrogenation   Oxidation   Half-n-half Clue   7. A substance which speeds up a chemical reaction without itself getting affected is known as a   Cation   Nucleus   Counter Ion   Catalyst   Half-n-half Clue