A titration to standardize a HCl solution was performed by taking 50.0ml hydrochloric acid in a flask with a few drops of phenolphthalein indicator. The burette was filled with 0.15 molar NaOH. The initial reading of the burette was 0.50ml and the final reading was 30.5ml. What is the concentration of the solution?

1 answer

volume NaOH = 30.5-0.50 = 30.0
mols NaOH = M x L = ?
mols HCl = mols NaOH since 1 mol NaOH - 1 mol HCl in the titration.
Then M HCl = mols HCl/L HCl.