Question

50 mL of 1 M oxalic acid (molar mass$=126{\text{gmol}}^{-1}$) is shaken with 0.5 g of wood charcoal. The final concentration of the solution after adsorption is 0.5 M. The amount of oxalic acid (in grams) adsorbed per gram of the charcoal is:

• A. 3.15
• B. 1.575
• C. 12.6
• D. 6.3

Answer 1

The correct option is D 6.3

$50mL\text{of}1M\text{oxalic acid}=50\times 1mmol$
$50mL\text{of}0.5M\text{oxalic acid}=50\times 0.5mmol$

Thus, oxalic acid adsorbed = $50(1-0.5)=50\times 0.5mmol$
$=\frac{50\times 0.5}{1000}\times 126g$
$=3.15g$
Charcoal taken = $0.5g$

Thus, oxalic acid adsorbed per gram of charcoal $=\frac{3.15}{0.5}=6.3g$