Find the concentration of sodium acetate when added to 0.1 M solution of acetic acid to form a buffer solution of $\mathrm{pH}=5.5$ ? $\left(\mathrm{pK}_{\mathrm{a}} ext { of } \mathrm{CH}_3 \mathrm{COOH}=4 \cdot 5 ight)$

Question

Find the concentration of sodium acetate when added to 0.1 M solution of acetic acid to form a buffer solution of $\mathrm{pH}=5.5$ ? $\left(\mathrm{pK}_{\mathrm{a}} 	ext { of } \mathrm{CH}_3 \mathrm{COOH}=4 \cdot 5ight)$

Aicharya · Accepted Answer

The Henderson-Hasselbalch equation provides the relationship between pH and buffer component concentrations:

$\mathrm{pH} = \mathrm{pK_a} + \log \frac{[\mathrm{CH_3COONa}]}{[\mathrm{CH_3COOH}]}$

Substituting the given values $\mathrm{pH} = 5.5$, $\mathrm{pK_a} = 4.5$, and $[\mathrm{CH_3COOH}] = 0.1\,\mathrm{M}$ yields:

$5.5 = 4.5 + \log \frac{[\mathrm{CH_3COONa}]}{0.1}$

Simplifying gives:

$1.0 = \log \frac{[\mathrm{CH_3COONa}]}{0.1}$

Taking the antilogarithm of both sides produces:

$10^{1.0} = \frac{[\mathrm{CH_3COONa}]}{0.1}$

Solving for the unknown concentration:

$[\mathrm{CH_3COONa}] = 10 \times 0.1 = 1.0\,\mathrm{M}$

Final answer: $1.0\,\mathrm{M}$

Find the concentration of sodium acetate when added to 0.1 M solution of acetic acid to form a buffer…

Solution