Acids and Bases

• Acids

  Chemicals that can be strong or weak, and can be corrosive or harmless
• Acids

  • Can be detected using indicators like litmus paper, which turns from blue to red in the presence of an acid
• Bases

  Chemicals that are chemically opposite to acids
• Bases

  • Can be detected using litmus paper, which turns from red to blue in the presence of a base
  • A base that dissolves in water is called an alkali
• Indicators

  Chemicals that change colour to show whether a substance is an acid or a base

  
• Neutral

  A substance that is neither acidic or basic
• pH scale

  A scale that tells you how acidic or basic a substance is, with 1-6 being acidic, 8-14 being basic, and 7 being neutral

  
• Universal indicator

  • Tells us the exact pH of a substance
• Acids are red in universal indicator, bases are blue
• Bases

  Are always cleaning agents used at home
• Chemical acids

  • Hydrochloric acid, Sulfuric acid
• Chemical bases/alkali

  • Sodium hydroxide
• Neutralisation

  Reaction between an acid and a base where salt and water is produced
• Acid + Base → Salt + Water
• Acid + Base

  • HCl + NaOH → NaCl + H2O
• Acid rain

  Rain that contains an acidity below pH 5.5, formed when SO2 from burning fossil fuels reacts with rainwater, and when nitric acid is formed from car exhaust fumes
• Problems caused by acid rain

  • Fish kills, kills trees, damages limestone buildings and statues
• Solving acid rain

  Power stations use limestone to neutralise acid fumes, cars have catalytic converters to remove harmful oxides from fumes
• Acids and bases

  • Vinegar, toothpaste, Dettol spray, All purpose cleaner, bar of soap piece, lime, lemon, windscreen wash, cif, rinse aid, baby shampoo