To 100 ml of M/2 oxalic acid solution 2 g of active charcoal is added. after absorption the strength of solution is reduced to M/4. Calculate the acid adsorbed by 1 g of charcoal.

To solve the problem of how much oxalic acid is adsorbed by 1 gram of activated charcoal, we need to break down the information given and perform some calculations step by step.

Understanding the Initial Conditions

We start with a solution of oxalic acid at a concentration of M/2. This means that in 1 liter (1000 ml) of solution, there are 0.5 moles of oxalic acid. Since we have 100 ml of this solution, we can calculate the number of moles present:

• Concentration (C) = M/2 = 0.5 moles/L
• Volume (V) = 100 ml = 0.1 L
• Moles of oxalic acid = C × V = 0.5 moles/L × 0.1 L = 0.05 moles

Calculating the Final Conditions

After adding 2 grams of activated charcoal and allowing it to adsorb some of the acid, the concentration of the solution decreases to M/4. This indicates that the remaining concentration of oxalic acid is now 0.25 moles/L. We can again calculate the number of moles in the 100 ml solution:

• New Concentration (C') = M/4 = 0.25 moles/L
• Volume (V) = 100 ml = 0.1 L
• Moles of oxalic acid after adsorption = C' × V = 0.25 moles/L × 0.1 L = 0.025 moles

Determining the Amount of Acid Adsorbed

Now, we can find out how many moles of oxalic acid were adsorbed by the charcoal. This is simply the difference between the initial moles and the final moles:

• Moles adsorbed = Initial moles - Final moles = 0.05 moles - 0.025 moles = 0.025 moles

Converting Moles to Grams

Next, we need to convert the moles of oxalic acid adsorbed into grams. The molar mass of oxalic acid (C2H2O4) is approximately 90 g/mol. Thus, we can calculate the mass of the acid adsorbed:

• Mass adsorbed = Moles adsorbed × Molar mass = 0.025 moles × 90 g/mol = 2.25 grams

Calculating Acid Adsorbed per Gram of Charcoal

Since we added 2 grams of activated charcoal, we can now find out how much acid is adsorbed by 1 gram of charcoal:

• Acid adsorbed per gram of charcoal = Total acid adsorbed / Mass of charcoal = 2.25 grams / 2 grams = 1.125 grams

Final Result

Therefore, the amount of oxalic acid adsorbed by 1 gram of activated charcoal is approximately 1.125 grams.