Question

A solution of 0.154 MNaOH

is used to titrate 18.5 mL
of a solution of H2SO4
:

H2SO4(aq)+2NaOH(aq)→2H2O(l)+Na2SO4(aq)


If 33.2 mL
of the NaOH
solution is required to reach the endpoint, what is the molarity of the H2SO4
solution?

Answer 1

To calculate the molarity of the H2SO4 solution, first determine the moles of NaOH used in titration, then calculate the moles of H2SO4, and finally divide by the volume of H2SO4 solution. Using given volumes and molarity of NaOH, the molarity of H2SO4 was found to be 0.1381 M.

Step-by-step explanation:

To determine the molarity of the H2SO4 solution in a titration with NaOH, we first need to calculate the moles of NaOH used and then use the stoichiometry of the reaction to find the moles of H2SO4. According to the balanced equation:

H2SO4(aq) + 2NaOH(aq) → Na2SO4(aq) + 2H2O(l)

The mole ratio of H2SO4 to NaOH is 1:2. To find the molarity of the H2SO4 solution, follow these steps:

1. Calculate the moles of NaOH used in the titration: moles NaOH = Molarity NaOH × Volume NaOH (in liters).
2. Use the stoichiometric relationship from the balanced equation to find the moles of H2SO4 that reacted (moles H2SO4 = moles NaOH / 2).
3. Divide the moles of H2SO4 by the volume of H2SO4 solution in liters to find the molarity of the H2SO4 solution.

Now applying this to the given problem:

1. Moles NaOH = 0.154 M × 0.0332 L = 0.00511 mol
2. Moles H2SO4 = 0.00511 mol / 2 = 0.002555 mol
3. Molarity H2SO4 = 0.002555 mol / 0.0185 L = 0.1381 M

The molarity of the H2SO4 solution is 0.1381 M.