Question

Which of the following compounds is the least acidic?

A) acetic acid (pka = 4.76)
B) carbonic acid (pka = 6.35)
C) Phosphoric acid (pKa = 2.15)
D) bicarbonate (pKa = 10.33)

Answer 1

Carbonic acid (H2CO3) is the least acidic compound among the given options.

Step-by-step explanation:

The least acidic compound among the given options is:

Carbonic acid (H₂CO₃, pKa = 6.35)

The strong acids have lower pKa values. Comparing the pKa values provided:

1. Phosphoric acid (H₃PO₄, pKa = 2.15) - Strongest acid
2. Acetic acid (CH₃COOH, pKa = 4.76)
3. Carbonic acid (H₂CO₃, pKa = 6.35) - Least acidic
4. Bicarbonate (HCO₃-, pKa = 10.33)

Therefore, carbonic acid is the least acidic compound among the given options.