Acids and Bases Grade 12 Questions, Answers and Notes Acids and bases are fundamental concepts in chemistry that play a crucial role in various chemical reactions and everyday life. Understanding their properties, behaviors, and applications is essential for success in Grade 12 chemistry and beyond. In this blog post, we’ll delve into some common questions, provide comprehensive answers, and offer valuable notes to help you master this important topic.
- What are acids and bases?
Acids are substances that donate protons (H⁺ ions) in aqueous solutions, while bases are substances that accept protons or donate hydroxide ions (OH⁻) in aqueous solutions. Acids typically have a sour taste, turn blue litmus paper red, and have a pH less than 7. Bases, on the other hand, have a bitter taste, feel slippery, turn red litmus paper blue, and have a pH greater than 7.
- What is the pH scale?
The pH scale is a measure of the acidity or basicity of a solution. It ranges from 0 to 14, with 7 being neutral. Solutions with a pH less than 7 are acidic, while those with a pH greater than 7 are basic. The pH of a solution is calculated using the formula: pH = -log[H⁺], where [H⁺] is the concentration of hydrogen ions in the solution.
- Give examples of common acids and bases.
Common acids include hydrochloric acid (HCl), sulfuric acid (H₂SO₄), nitric acid (HNO₃), acetic acid (CH₃COOH), and citric acid (found in citrus fruits). Common bases include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)₂), and ammonia (NH₃).
- What are the properties of acids?
Acids have several characteristic properties:
- They react with metals to produce hydrogen gas.
- They react with bases to form salts and water (neutralization reaction).
- They turn blue litmus paper red.
- They have a sour taste.
- They conduct electricity when dissolved in water.
- What are the properties of bases?
Bases also have distinctive properties:
- They feel slippery or soapy to the touch.
- They turn red litmus paper blue.
- They react with acids to form salts and water (neutralization reaction).
- They conduct electricity when dissolved in water.
- They are often used as cleaning agents due to their ability to react with oils and fats.
- Explain the concept of acid-base titration.
Acid-base titration is a technique used to determine the concentration of an unknown acid or base solution by reacting it with a solution of known concentration (titrant). The reaction is typically monitored using an indicator or a pH meter. The equivalence point is reached when the moles of acid are equal to the moles of base (or vice versa), indicating the end of the reaction.
- What is the difference between strong and weak acids/bases?
Strong acids and bases completely dissociate into ions when dissolved in water, resulting in high conductivity and a low pH (for acids) or high pH (for bases). Examples include hydrochloric acid and sodium hydroxide. Weak acids and bases only partially dissociate in water, resulting in lower conductivity and a pH closer to neutral. Examples include acetic acid and ammonia.
Useful Acids and Bases Grade 12 Questions, Answers and Notes pdf
