Question

An Erlenmeyer flask containing 20.0 mL of sulfuric acid of an unknown concentration was titrated with exactly 15.0 mL of 0.25 M NaOH solution to the second equivalence point. What was the concentration of sulfuric acid in the flask? H2SO4 (aq) + 2 NaOH (aq) → 2 H2O (l) + Na2SO4 (aq)

Answer 1

the concentration of sulfuric acid in the flask is 0.375 M

Step-by-step explanation:

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

Moles of NaOH = 15 x 0.25 /1000

= 0.00375

Moles of H2SO4 needed to neutralize = 0.00375 /2

= 0.001875

Molarity of H2SO4

= 0.001875 x 1000 /20

= 0.09375 M

concentration of sulfuric acid in the flask 0.09375 M

Moles

V2 = 20 ml

N2 =?

Substitute in the equation and find N2

N2 = 2 x 15 x 0.25 / 20

= 0.375 M

Thus, the concentration of sulfuric acid in the flask is 0.375 M