Question

50 ml of 1 M oxalic acid is shaken with 0.5 g wood charcoal. The final concentration of the solution after adsorption is 0.5 M. What is the amount of oxalic acid absorbed per gm of carbon?

• A. 3.15 g
• B. 3.45 g
• C. 6.30 g
• D. None

Answer 1

The correct option is C

6.30 g

No. of mmol of oxalic acid before shaking with charcoal : 50 X 1 = 50
No. of mmol of oxalic acid after shaking with charcoal : 50 X 0.5 = 25
0.5 g of charcoal absorbs = 50-25 = 25 mmol of oxalic acid
⇒ 1 g of charcoal absorbs = 50 mmol of oxalic acid
Mass of oxalic acid = no. of moles X molar mass
⇒ 50 X ${10}^{-3}$ X 126 = 6.3 g