Acids and Bases

• What does the pH scale measure?

  How acidic or alkaline a solution is
• What is the range of the pH 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 washing up liquid?

  Around 9
• What is the pH of bleach?

  Around 12
• What are indicators used for?

  To measure pH by changing color
• What is a wide range indicator?

  Changes color across a wide pH range
• How does a pH probe work?

  Measures pH electronically for accuracy
• Why are measurements that remove human judgment more reliable?

  They reduce guessing and subjective interpretation
• How is an acid defined?

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

  Hydrogen ions
• How is a base defined?

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

  A base soluble in water with pH > 7
• What ions do alkalis form in water?

  Hydroxide ions (OH⁻)
• What is produced in a neutralization reaction?

  A salt and water
• What is the reaction between hydrochloric acid and sodium hydroxide?

  Produces sodium chloride and water
• How can neutralization reactions be represented?

  In terms of hydrogen and hydroxide ions
• What is the pH of the products in a neutralization reaction?

  7
• What are some common acids?

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

  Sodium hydroxide and calcium carbonate
• What are the key concepts related to the pH scale?

  • pH measures acidity or alkalinity
  • Scale ranges from 0 to 14
  • Neutral pH is 7
  • Acids have pH < 7
  • Bases have pH > 7
  • Alkalis are soluble bases
• What methods are used to measure pH?

  1. Indicators (change color with pH)
  2. pH probes (electronic measurement)
• What happens in a neutralization reaction?

  • Acid and base react
  • Produce salt and water
  • pH of products is 7