Acids And Bases

• What do acids form in water?


  Acidic solutions
• What ions do acids produce in aqueous solution?


  Hydrogen ions, H+
• What is the chemical equation for hydrochloric acid in aqueous solution?


  HCl(aq) → H+(aq) + Cl-(aq)
• What pH values do acidic solutions have?


  Less than 7
• What do alkalis form in water?


  Alkaline solutions
• What ions do alkalis produce in aqueous solution?


  Hydroxide ions, OH-
• What is the chemical equation for sodium hydroxide in aqueous solution?


  NaOH(aq) → Na+(aq) + OH-(aq)
• What pH values do alkaline solutions have?


  Greater than 7
• What is a neutral solution?


  Neither acidic nor alkaline
• What pH value does a neutral solution have?


  7
• What does the pH scale measure?


  The acidity or alkalinity of a solution
• How can the pH of a solution be measured?


  Using a pH probe or universal indicator
• What is universal indicator?


  An acid-alkali indicator
• What do indicators show about a solution?


  Whether it is acidic, neutral, or alkaline
• What defines an acid in terms of ion production?


  • Produces more hydrogen ions than hydroxide ions when dissolved in water.
• What defines an acidic solution?

  • Having a pH lower than 7.
• What is a solution?


  • A mixture formed by a solute and a solvent.
• What is an ion?


  • An electrically charged particle formed when an atom or molecule gains or loses electrons.
• What is pH?


  • A scale of acidity or alkalinity.
  • Below 7 is acidic, above 7 is alkaline.
• What defines an alkali in terms of ion production?


  • Produces more hydroxide ions than hydrogen ions when dissolved in water.
• What defines an alkaline solution?

  • Having a pH greater than 7.
• What defines a neutral solution?


  • Neither acidic nor alkaline, with a pH of 7.
• What is an indicator?


  • A substance that has different colours depending on the pH of the solution it is in.
• What is a base?


  A substance that reacts with an acid to form a salt and water only
• What are examples of bases?


  Metal oxides and metal hydroxides
• What are alkalis?


  Bases that are soluble in water
• What happens when alkalis dissolve in water?


  They form alkaline solutions
• Is copper oxide an alkali?


  No, because it is insoluble in water
• Is sodium hydroxide an alkali?


  Yes, because it dissolves in water
• What is a neutralisation reaction?


  A reaction between an acid and a base
• What ions do acids provide in solution?

  Hydrogen ions, H+
• What ions do alkalis provide in solution?


  Hydroxide ions, OH-
• What occurs in acid-alkali neutralisation reactions?


  Hydrogen ions from the acid react with hydroxide ions from the alkali
• What is the chemical equation for the neutralisation reaction?


  $H^+$$(aq) +$$OH^-(aq) \rightarrow H_2O(l)$
• What is the pH of pure water?


  7
• How can a neutral solution be produced?


  If the correct amounts of acid and alkali react together
• How can the change in pH during a neutralisation reaction be measured?


  Using a pH probe and meter or universal indicator solution
• What is a base?


  A substance that reacts with an acid to neutralise it and produce a salt
• What is a salt?

  The substance formed when the hydrogen ion in an acid is replaced by a metal ion
• What does soluble mean?


  Able to dissolve in a solvent