High School

A student combined 37.2 mL of a 1.69 M KMnO₄ solution with 15.60 mL of a 0.891 M KMnO₄ solution. Calculate the concentration of the final solution.

a) 1.08 M
b) 1.15 M
c) 1.28 M
d) 1.45 M

Answer :

Final answer:

To calculate the concentration of the final KMnO4 solution after mixing, the number of moles of solute in each solution is determined, summed, and then divided by the total volume of the mixed solutions. The resulting molarity is 1.45 M. Hence the correct option would be option d.

Explanation:

The student is asking to calculate the concentration of the final KMnO4 solution after mixing two solutions with different volumes and molarities. To find the final concentration, first, we need to calculate the total number of moles of KMnO4 in the combined solution, and then divide it by the total volume of the mixed solutions.

  1. Calculate the number of moles of KMnO4 in each solution:
  2. Sum the moles of KMnO4:
    0.062868 mol + 0.0139016 mol = 0.0767696 mol
  3. Convert the volumes from mL to L and sum them:
    37.2 mL / 1000 + 15.60 mL / 1000 = 0.0528 L
  4. Divide the total moles by the total volume for the final molarity:
    0.0767696 mol / 0.0528 L = 1.4530235 M

The final concentration of the KMnO4 solution, rounded to two decimal places, is 1.45 M, which corresponds to answer choice d).

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