1. A pH below 7 indicates _______.   alkalinity   acidity   purity of the sample   presence of ions   Hint Half-n-half Clue   2. What gas is evolved when dilute sulfuric acid is added to zinc?   Hydrogen   Hydrogen Peroxide   Sulfur Dioxide   Argon   Half-n-half Clue   3. Solubility of a substance in a solvent usually increases with an increase in temperature.   True   False   4. Which of the following is a chemical change?   Boiling of water   Freezing of water   Dissolving of salt in water   Rusting of iron   Half-n-half Clue   5. Catalysts speed up the rate of chemical reactions.   True   False   6. The 'fizz' in soft drinks is caused by _______.   nitrogen   Carbon dioxide   hydrogen   helium   Half-n-half Clue   7. A substance that speeds up the rate of a chemical reaction without undergoing any change itself is known as a _______.   counter ion   catalyst   nucleus   cation   Half-n-half Clue