AP Chemistry / Unit 8: Acids and Bases

8.7 pH and pKa

3 practice questions

Notes

$pK_a=-\log K_a$; smaller $pK_a$ = stronger acid.
If $pH<pK_a$: mostly HA (protonated). If $pH>pK_a$: mostly $\mathrm{A^-}$.

Practice

An acid has $pK_a=4.8$ in a solution at pH 7. Its main form:

Which acid is strongest?

At pH = $pK_a$:

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