Question

Explain why a buffer can be prepared from a mixture of NH₄Cl and NaOH but not from NH₃ and NaOH.

a) NH₄Cl is a weak acid, providing a source of H⁺ ions; NH₃ is a weak base, providing a source of OH⁻ ions.
b) NH₄Cl is a strong acid, providing a source of H⁺ ions; NH₃ is a weak base, providing a source of OH⁻ ions.
c) NH₄Cl is a weak base, providing a source of OH⁻ ions; NH₃ is a strong base, providing a source of OH⁻ ions.
d) NH₄Cl is a strong base, providing a source of OH⁻ ions; NH₃ is a weak base, providing a source of OH⁻ ions.

Answer 1

A buffer can be prepared from NH4Cl and NaOH because a. NH4Cl is a weak acid and NH3 is a weak base. However, a buffer cannot be prepared from NH3 and NaOH because NaOH is a strong base.

Step-by-step explanation:

A mixture of a weak acid and its conjugate base (or a mixture of a weak base and its conjugate acid) is called a buffer solution, or a buffer. Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added.

For example, a buffer can be prepared from a mixture of NH4Cl and NaOH because a. NH4Cl is a weak acid that provides a source of H+ ions, and NH3 is a weak base that provides a source of OH- ions. However, a buffer cannot be prepared from NH3 and NaOH because NaOH is a strong base that does not act as a buffer with NH3.