Buffers: Definition and Applications

What is a buffer solution?

• A strong acid that resists changes in pH

• A compound that increases pH

• A mixture that resists changes in pH upon addition of acid or base

• A salt that neutralizes water

Why are buffer systems necessary in solutions?

• To make solutions taste better

• To increase the solubility of salts

• To maintain a constant pH

• To make the solution acidic

What happens if a solution absorbs CO₂ from the air?

• Becomes alkaline

• Becomes more stable

• Becomes acidic

• No effect

Which of the following would NOT affect pH in a stored solution?

• CO₂ absorption

• Salt precipitation

• Alkaline impurities from glass

• None of the above

Which of the following is an acidic buffer?

• NH₄OH / NH₄Cl

• CH₃COOH / CH₃COONa

• NaOH / NaCl

• HCl / NaCl

Which of these is a basic buffer system?

• CH₃COOH / CH₃COONa

• H₂CO₃ / NaHCO₃

• NH₄OH / NH₄Cl

• H₃PO₄ / NaH₂PO₄

Acidic buffers typically consist of:

• Weak base and salt of weak base

• Strong acid and salt

• Weak acid and its salt with a strong base

• Strong acid and strong base

Basic buffers typically consist of:

• Weak base and its salt with a strong acid

• Strong base and weak acid

• Strong acid and its salt

• Weak acid and strong base

What happens when HCl is added to an acetic acid/sodium acetate buffer?

• Buffer becomes basic

• Buffer is destroyed

• H⁺ ions are neutralized by acetate ions

• pH drops drastically

What is the primary product when NaOH is added to an acidic buffer?

• Salt

• Water

• HCl

• Acetate