DAT DAT - Dental Admission General Chemistry: Acid-Base Chemistry 2

Question 1

A buffer solution resists pH changes upon addition of small amounts of:

Accepted Answer

Strong acid or strong base

Answer

A buffer resists pH changes when small amounts of strong acid or strong base are added by neutralizing them through its weak acid/conjugate base equilibrium.

Question 2

The Henderson-Hasselbalch equation for a buffer is: pH =

Accepted Answer

pKa + log([A⁻]/[HA])

Answer

The Henderson-Hasselbalch equation pH = pKa + log([A⁻]/[HA]) relates buffer pH to the pKa and ratio of conjugate base to weak acid.

Question 3

Which combination forms an effective buffer?

Accepted Answer

CH₃COOH and CH₃COONa

Answer

An effective buffer requires a weak acid and its conjugate base, such as acetic acid (CH₃COOH) and sodium acetate (CH₃COONa).

Question 4

The bicarbonate buffer system in blood maintains physiological pH at approximately:

Accepted Answer

7.4

Answer

The H₂CO₃/HCO₃⁻ buffer system is the primary blood buffer, maintaining pH at approximately 7.4 (normal range 7.35–7.45).

Question 5

A buffer is most effective when the solution pH is close to:

Accepted Answer

The pKa of the weak acid component

Answer

A buffer provides maximum buffering capacity when pH is within ±1 unit of the weak acid's pKa.

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DAT DAT - Dental Admission General Chemistry: Acid-Base Chemistry 2