Exams › NEET › Chemistry

A physician wishes to prepare a buffer solution of pH = 3.58 that efficiently resists a change in pH yet contains only small concentrations of the buffering agents. Which one of the following weak acids together with its sodium salt would be the best to use?

1. m-chlorobenzoic acid (pKa = 3.98)
2. p-chlorobenzoic acid (pKa = 4.41)
3. 2,5-dihydroxy benzoic acid (pKa = 2.97)
4. Acetoacetic acid (pKa = 3.58)

Correct answer: Acetoacetic acid (pKa = 3.58)

Solution

The best buffer is formed when the pKa of the weak acid is equal to the desired pH. Since the pKa of acetoacetic acid is 3.58, it matches the desired pH exactly, making it the optimal choice.

Related NEET Chemistry questions

• A beaker contains a saturated solution of copper(l) chloride. Copper(l) chloride is slightly soluble salt with a solubility product of \( 1.2 \times 10^{-6} \) Which of the following salts when added to the solution would precipitate copper(l) chloride?
• The function of 'buffer solution' is:
• When \( C a(O H)_{2} \) attains solubility equilibrium, the:
• Predict if there will be any precipitate by mixing \( 50 \mathrm{mL} \) of \( 0.01 \mathrm{M} \) NaCl and 50 mL of \( 0.01 \mathrm{M} A g N O_{3} \) solution. The solubility product of \( A g C l \) is \( 1.5 \times \) \( 10^{-10} \)
• Calculate the ratio of \( H C O O^{-} \) and \( F^{-} \) in a mixture of \( 0.2 M \) HCOOH \( \left(K_{a}=\right. \) \( \left.2 \times 10^{-4}\right) \) and \( 0.1 M H F\left(K_{a}=6.6 \times\right. \) \( \left.10^{-4}\right) \)
• What is the [OH⁻] in the final solution prepared by mixing 20.0 mL of 0.050 M HCl with 30.0 mL of 0.10 M Ba(OH)₂?

⚔️ Practice NEET Chemistry free + battle 1v1 →