The concentrations of acetic acid and sodium acetate is a buffer solution of total moalrity 0.39 M and having a pH of 4.4 if the $K_a$ of acetic acid is  is $1.83\times {10}^{-5}$ is

$K_a=10-4.2=6.31\times {10}^{-5}$,$log\frac{\left[Salt\right]}{\left[Acid\right]}=pH-p{K}_a$

$=pH+log{K}_a$=$4.4+log(1.83\times {10}^{-5})$= 4.4 – 4.7 = - 0.3 

$\frac{\left[Salt\right]}{\left[Acid\right]}={10}^{-0.3}=0.5$  $1+\frac{\left[Salt\right]}{\left[Acid\right]}=1+0.5$

$\frac{\left[Acid\right]+\left[Salt\right]}{\left[Acid\right]}=1.5$ , $\frac{totalmolarity}{\left[Acid\right]}=1.5$, $\frac{0.39}{\left[Acid\right]}=1.5$

$\left[Acid\right]=\frac{0.39}{1.5}=0.26$  [Salt] = 0.39 – 0.26 = 0.13