A tank car carrying concentrated hydrochloric acid overturns and spills into a small irrigation canal. An analysis of the canal water must be performed before chemists will decide how to remediate the spill. A chemist titrates a 200-mL sample of water from the canal with a 0.00100 M NaOH solution. What is the molar concentration of the acid in the canal if 23.20 mL of the base solution are needed to reach the equivalence point?

Strategy

As in other equation stoichiometry problems, we must perform the following steps:

(1) Write the balanced equation;

(2) Use the information in the problem to determine the number of moles of the given substance (NaOH in this problem);

(3) Use the coefficients in the equation to convert from moles of NaOH to moles of the desired substance, hydrochloric acid;

(4) Use the number of moles of the acid calculated in step 3 and the measured volume of sample to determine the concentration of acid.

Transcribed Image Text:

Volume (L) of OH (aq) solution Molarity of OH(aq) solution Moles of OH(aq) Coefficients in chemical equation Moles of H*(aq) Volume (L) of H* (aq) solution Molarity of H+ (aq) solution