Question

The $pH$ of a simple sodium acetate buffer is given by $pH=p{K}_a+\log \frac{\left[Salt\right]}{\left[Acid\right]}$
$K_a$ of acetic acid $=1.8\times {10}^{-5}$

If [Salt]=[Acid] $=0.1M$, the $pH$ of the solution would be about:

• A. $7$
• B. $4.74$
• C. $5.3$
• D. $1.4$

Answer 1

The correct option is B $4.74$

$\left[Salt\right]=0.1M,\left[Acid\right]=0.1M$

$K_a=1.8\times {10}^{-5};pH=-\log K_a+\log \frac{\left[Salt\right]}{\left[Acid\right]}$

$=-\log 1.8\times {10}^{-5}+\log \frac{0.1}{0.1}=-\log 1.8\times {10}^{-5}$

$pH=4.74$