200 ml of 1 M H₂SO₄, 300 ml of 3 M HCl and 100 ml of 2 M HCl are mixed and made up to 1 litre. The proton concentration in the resulting solution is:

• A) 1.25 M
• B) 1.5 M
• C) 2.5 M
• D) 0.75 M

To find the proton concentration in the resulting solution after mixing the given volumes and molarities of sulfuric acid (H₂SO₄) and hydrochloric acid (HCl), we need to calculate the total moles of protons contributed by each acid and then determine the final concentration in the total volume of 1 liter.

Step 1: Calculate Moles of Protons from Each Acid

• H₂SO₄: 200 ml of 1 M H₂SO₄ contributes 2 moles of protons per mole of acid.
• Moles of H₂SO₄ = 1 M × 0.2 L = 0.2 moles
• Protons from H₂SO₄ = 0.2 moles × 2 = 0.4 moles
• HCl (first solution): 300 ml of 3 M HCl contributes 1 mole of protons per mole of acid.
• Moles of HCl = 3 M × 0.3 L = 0.9 moles
• Protons from HCl = 0.9 moles × 1 = 0.9 moles
• HCl (second solution): 100 ml of 2 M HCl also contributes 1 mole of protons per mole of acid.
• Moles of HCl = 2 M × 0.1 L = 0.2 moles
• Protons from HCl = 0.2 moles × 1 = 0.2 moles

Step 2: Total Moles of Protons

Now, we can sum the moles of protons from all sources:

• Total protons = 0.4 moles (from H₂SO₄) + 0.9 moles (from first HCl) + 0.2 moles (from second HCl) = 1.5 moles

Step 3: Calculate Proton Concentration

The total volume of the solution is 1 liter. Therefore, the concentration of protons is:

• Proton concentration = Total moles of protons / Total volume = 1.5 moles / 1 L = 1.5 M

Final Answer

The proton concentration in the resulting solution is 1.5 M, which corresponds to option B.