Chemistry

Problem

A laboratory protocol requires

500\,\text{mL}

of an acetic acid–acetate buffer initially at

pH = 4.75

(

pK_{a} = 4.75

) that can neutralize up to

0.020\,\text{mol}

of added HCl while keeping the pH change within

\pm 0.10

. If the buffer is prepared so that

[\text{CH}_3\text{COOH}] = [\text{CH}_3\text{COO}^-]

initially, what is the minimum total buffer concentration (

[\text{CH}_3\text{COOH}] + [\text{CH}_3\text{COO}^-]

) that will meet the requirement? a)

0.35\,\text{M}

0.70\,\text{M}

0.16\,\text{M}

0.31\,\text{M}