3g of activated charcoal was added to 50 mL of acetic acid solution $(0.06\;N)$ in a flask. After an hour it was filtered was found to be $0.042\;N$ . The amount of acetic acid absorbed (per gram of charcoal ) is :

Question

$\begin{array}{1 1} 54\;mg \\ 18\;mg\\ 36\;mg \\ 42\;mg \end{array}$