Acid-Base Concepts and pH_Pre-Lecture1

According to the Brønsted–Lowry definition, an acid is a substance that:

• Accepts a proton (H⁺)
  

• 
  Donates a proton (H⁺)
  

• 
  Produces OH⁻ ions in solution
  

• 
  Increases the pH of water

Black coffee has a pH of about 5. Which statement is correct?

• It is neutral.
  

• It is slightly acidic.

• 
  It is strongly basic.
  

• It has the same [H⁺] as pure water.

Which of the following pairs are conjugate acid–base partners?

• H₂O and OH⁻

• HCl and NaCl
  

• 
  Na⁺ and NaOH
  

• d) NH₃ and OH⁻

At 25 °C, the concentration of H⁺ ions in pure water is 1.0 × 10⁻⁷ M. What is the pH of pure water?

• 0.0
  

• 1.0 × 10⁷
  

• 14.0
  

• 
  7.0

Which scenario best illustrates the importance of acid–base chemistry in biology?

• Mixing vinegar and baking soda to make bubbles
  

• The body maintaining blood pH close to 7.4

• Adding lemon juice to tea for flavor
  

• Cleaning with soap and water