Acids and Bases

• What does the pH scale measure?

  How acidic or alkaline a solution is
• What is the pH range of the scale?

  0 to 14
• What pH value indicates a neutral solution?

  7
• What is the pH of stomach acid?

  Around 2
• What is the pH of acid rain?

  Around 4
• What is the pH of bleach?

  Around 12
• What is the pH of washing up liquid?

  Around 9
• What are the two main ways to measure pH?

  • Using indicators (chemical dyes)
  • Using a pH probe and meter
• What do indicators do?

  Change color depending on the pH
• What is a wide range indicator?

  Changes color across a wide pH range
• What does the pH scale measure?

  How acidic or alkaline a solution is
• What is the pH range of the scale?

  0 to 14
• What pH value indicates a neutral solution?

  7
• What is the most common example of a wide range indicator?

  Universal indicator
• How does a pH probe work?

  Measures pH electronically in solutions
• What is the pH of stomach acid?

  Around 2
• What is the pH of acid rain?

  Around 4
• Why is a pH probe more reliable than indicators?

  It removes human judgment in measurement
• What is the pH of washing up liquid?

  Around 9
• How is an acid defined?

  Forms solutions with pH less than 7
• What do acids release in water?

  Hydrogen ions
• What is the pH of bleach?

  Around 12
• What do indicators do?

  Change color depending on the pH
• What are the methods to measure pH?

  • Using indicators (chemical dyes)
  • Using a pH probe and meter
• How is a base defined?

  Any substance with pH greater than 7
• What is an alkali?

  A base soluble in water
• What is a wide range indicator?

  Changes color across a wide pH range
• What ions do alkalis form in water?

  Hydroxide ions (OH⁻)
• What is the most common example of a wide range indicator?

  Universal indicator
• What happens in a neutralization reaction?

  • Acid and base react
  • Produces salt and water
  • pH of products is 7
• What colors does the universal indicator show?

  Deep red to bluey purple
• What is the reaction between hydrochloric acid and sodium hydroxide?

  Produces sodium chloride and water
• How does a pH probe work?

  Measures pH electronically in solutions
• What do H⁺ and OH⁻ ions form in neutralization?

  Water (H₂O)
• What is the pH of neutral products in a neutralization reaction?

  7
• What are some common acids and bases?

  • Acids: hydrochloric, sulfuric, nitric
  • Bases: sodium hydroxide, calcium carbonate
• Why is a pH probe more accurate than an indicator?

  It removes human judgment in measurement
• What are the main acids mentioned?

  Hydrochloric, sulfuric, and nitric acid
• What are common bases mentioned?

  Sodium hydroxide and calcium carbonate
• How is an acid defined?

  Forms solutions with pH less than 7