1. Which of the following is a chemical change?   Boiling of water   Freezing of water   Rusting of iron   Dissolving of salt in water   Hint Half-n-half Clue   2. Which of the following gases is green in color?   Hydrogen   Krypton   Chlorine   Neon   Half-n-half Clue   3. The two allotropes of phosphorus are _______ and _______.   Red, Yellow   Crystalline, Amorphous   Rhombic, Monoclinic   Alpha, Beta   Half-n-half Clue   4. Catalysts speed up the rate of chemical reactions.   True   False   5. Lemon juice is _______ in nature.   neutral   acidic   metallic   basic   Half-n-half Clue   6. Which of the following is not an acid?   NaOH   H2SO4   HNO3   HCl   Half-n-half Clue   7. What gas is evolved when dilute sulfuric acid is added to zinc?   Argon   Hydrogen   Hydrogen Peroxide   Sulfur Dioxide   Half-n-half Clue