Question

In an experiment, 25.0 mL of 0.145 M H2SO4 react completely with 54.1 mL of a NaOH solution. What is the molar concentration (M) of the NaOH solution? 2 NaOH(aq) + H2SO4(aq) → Na2SO4(aq) + 2H2O a. 2.52 M b. 0.134 M c. 0.323 M d. 1.67 M e. 0.250 M

Please show work! Thanks

Answer 1

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

Molarity of H2SO4 = number of moles of H2SO4 / volume of solution in L

0.145 m = Number of moles of H2SO4 / 0.025 L

Number of moles of H2SO4 = 0.145*0.025 = 0.003625 mole of H2SO4

From the balanced equation we can say that

1 mole of H2SO4 requires 2 mole of NaOH so

0.003625 mole of H2SO4 will require

= 0.003625 mole of H2SO4 *(2 mole of NaOH /1 mole of H2SO4 )

= 0.00725 mole of NaOH

molar concentration of NaOH = number of moles of NaOH / volume of solution in L

Molar concentration of NaOH = 0.00725 mole / 0.0541 L = 0.134 M

Therefore, option B is correct