Question

Which of the following mixtures act(s) as a buffer solution?

• A. NaOH+CH3COOH (1:1 mole ratio)
• B. NH4OH+HCl (2:1 mole ratio)
• C. CH3COOH+NaOH (2:1 mole ratio)
• D. CH3COOH+NaOH (1:2 mole ratio)

Answer 1

Answer: (B), (C)

NH4OH+HCl (2:1 mole ratio)

Answer 2

An acidic buffer comprises a combination of a weak acid and one of its salts, while a basic buffer is formed by mixing a weak base with one of its salts. Among the provided mixtures, B, C, and D possess buffer properties.

(A) The mixture NaOH+HCOONa cannot function as a buffer due to the presence of a strong base and a salt derived from a weak acid.

(B) The blend of Borax + boric acid acts as a buffer since it encompasses a weak acid (boric acid) along with its salt (borax), in addition to a strong base.

(C) The combination NaH 2 ​ PO 4 ​ +Na 2 ​ HPO 4 ​ qualifies as a buffer, given that it comprises a weak acid (monosodium dihydrogen phosphate) and its corresponding salt (disodium monohydrogen phosphate), alongside the strong base NaOH.

(D) NH 4 ​ Cl+NH 4 ​ OH functions as a buffer by containing a weak base, ammonium hydroxide, and its salt, ammonium chloride, alongside a strong acid, HCl.

The correct answer is/are option(s):
(B): NH4OH+HCl (2:1 mole ratio)
(C): CH3COOH+NaOH (2:1 mole ratio)