Question

$50$ ml of $1$ M oxalic acid is shaken with $0.5$ gm of wood charcoal. The final concentration of the solution after adsorption is $0.5M$. Amount of oxalic acid absorbed per gm of charcoal is:

• A. $3.45$ gm
• B. $3.15$ gm
• C. $6.30$ gm
• D. none of these

Answer 1

The correct option is C $6.30$ gm

No. of moles in 50 ml of 1 M oxalic acid is = $\frac{50L}{1000}\times 1M=0.05$ moles of oxalic acid.

After adsorption, remaining moles of oxalic acid=$\frac{50L}{1000}\times 0.5M=0.025$ moles.

Thus, moles that adsorb on charcoal is $=0.05-0.025=0.025$ moles of oxalic acid.

Therefore, 0.025 moles of oxalic acid adsorb on 0.5 g of charcoal.

1 gram of charcoal moles adsorb=$\frac{0.025}{0.5}=0.05$ moles of oxalic acid.

Amount of oxalic acid adsorbed per gram of charcoal = $0.05\times 126g/mole=6.30$grams

Thus, $6.30g$ of oxalic acid adsorb per gram of charcoal.

Hence, option C is correct.