A 35.00 mL sample of an H2SO4 solution of unknown concentration is titrated with a 0.1222 M KOH solution. A volume of 42.22 mL of KOH was required to reach the equivalence point. Need to find concentration for H2SO4

0.07 M

Explanation:

Given data:

Volume of H₂SO₄ = 35.00 mL  (35/1000 = 0.035 L)

Molarity of KOH =0.1222 M

Volume of KOH = 42.22 mL (42.22/1000 = 0.0422 L)

Molarity /concentration of H₂SO₄ = ?

Solution:

Chemical equation:

H₂SO₄  +  2KOH     →     K₂SO₄ + 2H₂O

Number of moles of KOH:

Molarity = number of moles / volume in L

0.1222 M = number of moles / 0.0422 L

0.0422 L×0.1222 M = number of moles

Number of moles = 0.005 mol

Now we will compare the moles of KOH with H₂SO₄ from balance chemical equation.

                      KOH               :            H₂SO₄

                         2                 :                 1

                    0.005              :            1/2×0.005 = 0.0025 mol

Concentration of H₂SO₄:

Molarity = number of moles / volume in L

Molarity = 0.0025 mol / 0.035 L

Molarity = 0.07 M