Acids and bases

• What does a neutral solution contain in terms of ion concentration?


  Equal concentration of hydrogen (H+) and hydroxide (OH–) ions
• What characterizes an acidic solution?

  The concentration of hydrogen ions (H+) is higher than that of hydroxide ions (OH–)
• What are hydrogen ions responsible for in acids?


  They are responsible for the properties of acids
• How do acidic gases behave in organic solvents?


  They do not behave as acids and cannot dissociate in organic solvents
• What happens when hydrogen chloride dissociates in water?


  It produces hydrochloric acid
• Are all substances containing hydrogen considered acids?


  No, substances like methane (CH4) and ammonia (NH3) do not produce H+ ions in water
• What are some examples of acids and their chemical formulas?

  • Sulfuric acid: H2SO4 → H+ (aq), SO42– (aq)
  • Hydrochloric acid: HCl → H+ (aq), Cl– (aq)
  • Nitric acid: HNO3 → H+ (aq), NO3– (aq)
  • Ethanoic acid: CH3COOH → H+ (aq), CH3COO– (aq)
• What is the definition of an acid in aqueous solution?


  An acid is a substance that produces hydrogen ions (H+) in aqueous solution
• What is produced when an acid reacts with a reactive metal?


  Salt and hydrogen gas
• What is the word equation for the reaction between hydrochloric acid and zinc?


  Hydrochloric acid + Zinc → Zinc chloride + Hydrogen
• What is the chemical equation for the reaction of sulfuric acid with magnesium?

  H2SO4 + Mg → MgSO4 + H2
• How can hydrogen gas be tested?


  By placing a lighted splint at the mouth of the test tube, producing a 'pop' sound
• What is produced when an acid reacts with metal carbonates?


  Salt, water, and carbon dioxide
• What is the word equation for the reaction between nitric acid and copper (II) carbonate?

  Nitric acid + Copper (II) carbonate → Copper (II) nitrate + Water + Carbon dioxide
• What is the chemical equation for the reaction of hydrochloric acid with calcium carbonate?


  2 HCl + CaCO3 → CaCl2 + H2O + CO2
• What happens to limestone buildings when they come into contact with acid rain?


  They are eroded due to the reaction with calcium carbonate
• What is a neutralization reaction?


  It is a reaction between an acid and a base to produce salt and water
• What is produced when an acid reacts with metal oxides or hydroxides?


  Salt and water
• What is the definition of a base?


  A base reacts with an acid to produce a salt and water
• What is the difference between a base and an alkali?


  An alkali is a soluble base that produces hydroxide ions in water
• What are some examples of alkalis and their chemical formulas?


  • Potassium hydroxide: KOH → K+ (aq), OH– (aq)
  • Sodium hydroxide: NaOH → Na+ (aq), OH– (aq)
  • Calcium hydroxide: Ca(OH)2 → Ca2+ (aq), OH– (aq)
• What are the physical properties of alkalis?


  They have a bitter taste, soapy feel, conduct electricity, turn red litmus paper blue, and have a pH greater than 7
• What is the chemical reaction of a base with an acid?

  Base + Acid → Salt + Water
• What is produced when sodium hydroxide reacts with ammonium chloride?


  Sodium chloride, water, and ammonia gas
• What is the chemical equation for the reaction of sodium hydroxide with ammonium chloride?

  NaOH + NH4Cl → NaCl + H2O + NH3
• What is the chemical formula for potassium hydroxide?


  KOH
• What are the ions present in potassium hydroxide when dissolved in water?


  K⁺ (aq) and OH^- (aq)
• What is the chemical formula for sodium hydroxide?


  NaOH
• What are the ions present in sodium hydroxide when dissolved in water?


  Na⁺ (aq) and OH^- (aq)
• What is the chemical formula for calcium hydroxide?


  Ca(OH)2
• What are the ions present in calcium hydroxide when dissolved in water?


  Ca²⁺ (aq) and OH^- (aq)
• What is the physical property of alkali that describes its taste and texture?


  Bitter taste and soapy feel
• Why do alkalis conduct electricity in aqueous solutions?


  Due to the presence of mobile ions
• What happens to red litmus paper when it comes into contact with alkali?


  It turns blue
• What is the pH value of alkali?


  More than 7 (pH > 7)
• What is the general reaction of an alkali with an acid?


  It forms salt and water (Neutralisation)
• What is the reaction of an alkali with ammonium salt when warmed?


  • Forms salt
  • Produces water
  • Releases ammonia gas
• Write the word equation for the reaction between sodium hydroxide and ammonium chloride.

  Sodium hydroxide + Ammonium chloride → Sodium chloride + Water + Ammonia
• Write the chemical equation for the reaction between sodium hydroxide and ammonium chloride.

  NaOH + NH₄Cl → NaCl + H₂O + NH₃
• Write the word equation for the reaction between calcium hydroxide and ammonium carbonate.

  Calcium hydroxide + Ammonium carbonate → Calcium carbonate + Water + Ammonia gas