acids & bases

• What does the pH scale measure?

  The pH scale measures how acidic or alkaline a solution is.
• What is the range of the pH scale?

  The pH scale ranges from 0 to 14.
• What pH value indicates a neutral solution?

  A neutral solution has a pH of 7.
• What is the pH of stomach acid?

  The pH of stomach acid is around 2.
• What are the two main methods to measure pH?

  • Using indicators (chemical dyes that change color with pH)
  • Using a pH probe connected to a pH meter
• What is a wide range indicator?

  A wide range indicator is a mixture of dyes that changes color across a wide range of pH values.
• What is the most common example of a pH indicator?

  The most common example of a pH indicator is universal indicator.
• How does universal indicator show pH levels?

  Universal indicator shows pH levels by changing colors from deep red (acidic) to bluey purple (alkaline).
• What is the benefit of using a pH probe over an indicator?

  A pH probe provides more accurate and precise measurements than indicators.
• How is an acid defined in terms of pH?

  An acid is defined as any substance that forms aqueous solutions with a pH of less than 7.
• What do acids release in water that makes the solution acidic?

  Acids release hydrogen ions in water.
• How is a base defined?

  A base is defined as any substance with a pH greater than 7 that can neutralise an acid
• What is an alkali?

  An alkali is a base that dissolves in water to form a solution with a pH greater than 7.
• What ions do alkalis form in water?

  Alkalis form hydroxide ions (OH-) in water.
• What happens during a neutralization reaction?

  • H+ ions from the acid react with OH- ions from the base
  • Produces a salt and water
  • The pH of the products is 7 (neutral)
• What is the reaction between hydrochloric acid and sodium hydroxide?

  Hydrochloric acid reacts with sodium hydroxide to form sodium chloride and water.
• How can neutralization reactions be represented in terms of ions?

  Neutralization can be represented as H+ from the acid and OH- from the base combining to form H20
• What is the pH of the products in a neutralization reaction?

  The pH of the products in a neutralization reaction is 7.
• What are the main acids mentioned in the material?

  The main acids are hydrochloric acid, sulfuric acid, and nitric acid.
• What are the common bases mentioned in the material?

  The common bases are generally hydroxides or carbonates like sodium hydroxide and calcium carbonate.
• give an example of a household product that is acidic


  car battery acid/lemon juice/vinegar
• give an example of a household product that is alkaline


  washing-up liquid/bleach/drain cleaner