Question

A 25-mL solution of H2SO4 is completely neutralized by 18 mL of 1.0M NaOH. What is the concentration of the H2SO4?H2SO4(aq) +2NaOH(aq) → Na2SO4(aq) + 2H2O(l)

Answer 1

1) Balanced chemical reaction

     H2SO4 (aq) + 2NaOH(aq) ----> Na2SO4(aq) + 2 H2O(liq)

2) Molar ratios

1 mol H2SO4 : 2 mol NaOH : 1 mol Na2SO4

3) Number of moles of NaOH


M = n / V => n = M * V = 1.0 M * 0.018 liter = 0.018 mol
of NaOH.


4) Determine the number of moles of H2SO4 using proportionality

1 mol H2SO4 / 2 mol NaOH = x / 0.018 mol NaOH

Solve for x:

x = 0.018 mol NaOH * 1 mol H2SO4 / 2 mol NaOH =0.009 mol H2SO4


5) Calculate the molarity using 0.009 mol and 25 mililiters

M = n / V = 0.009 mol / 0.025 liter = 0.36 M 

Answer: the concentration of the H2SO4 is 0.36 M