Question

What are the

major ionization
state(s) for succinic
acid at pH 3.2, 4.2,
5.2, and 6.2? pK= 4.21.

Answer 1

The major ionization state is at pH of 6,2.

Step-by-step explanation:

Succinic acid HOOC(CH₂)₂COOH has as equilibrium:

HOOC(CH₂)₂COOH ⇄ HOOC(CH₂)₂COO⁻ + H⁺; pka = 4,21

The Henderson-Hasselbalch formula:

pH = pka + log₁₀
`([HOOC(CH_(2))_(2)COO^-])/([HOOC(CH_(2))_(2)COOH])`

For a pH of 3,2:

3,2 = 4,21 + log₁₀
`([HOOC(CH_(2))_(2)COO^-])/([HOOC(CH_(2))_(2)COOH])`

0,0977 =
`([HOOC(CH_(2))_(2)COO^-])/([HOOC(CH_(2))_(2)COOH])`

For a pH of 4,2:

4,2 = 4,21 + log₁₀
`([HOOC(CH_(2))_(2)COO^-])/([HOOC(CH_(2))_(2)COOH])`

0,977 =
`([HOOC(CH_(2))_(2)COO^-])/([HOOC(CH_(2))_(2)COOH])`

For a pH of 5,2:

5,2 = 4,21 + log₁₀
`([HOOC(CH_(2))_(2)COO^-])/([HOOC(CH_(2))_(2)COOH])`

9,77 =
`([HOOC(CH_(2))_(2)COO^-])/([HOOC(CH_(2))_(2)COOH])`

For a pH of 6,2:

6,2 = 4,21 + log₁₀
`([HOOC(CH_(2))_(2)COO^-])/([HOOC(CH_(2))_(2)COOH])`

97,7 =
`([HOOC(CH_(2))_(2)COO^-])/([HOOC(CH_(2))_(2)COOH])`

Thus, the major ionization state is at pH of 6,2.