Anonymous
Anonymous asked in Science & MathematicsChemistry · 1 month ago

# Chem Help?

You are given solutions of hydrochloric acid and sodium hydroxide and must determine their concentrations. You use 18.45 mL of sodium hydroxide to titrate 50.00 mL of 0.0782 M sulfuric acid and 27.52 mL of that same NaOH solution to titrate 100.00 mL of the HCl solution. Determine the unknown concentrations of the hydrochloric acid and the sodium hydroxide.

NaOH(aq) + H2SO4(aq) -> Na2SO4(aq) + H2O(l)

HCl(aq) + NaOH(aq) -> NaCl(aq) + H2O(l)

Relevance
• H2SO4(aq) + 2 NaOH(aq) = Na2SO4(aq) + 2 H2O(l)

moles of H2SO4 at the equivalence point = 0.050L * 0.0782 moles / L = 0.00391

moles of NaOH at that point = 0.00391 *2 = 0.00782 moles

these are in 0.01845 L so M = 0.00782 mol / 0.01845  = 0.424 M NaOH

in 0.02752 L of the NaOH we have 0.424 mol / L *  0.02752 L = 0.0116 moles

HCl(aq) + NaOH(aq) -> NaCl(aq) + H2O(l)

so moles of HCl at the equivalence point = = 0.0116 moles

these are in 0.10 L so M = 0.0116 moles / 0.10L = 0.117 M HCl