Question

The flask contains 10.0 mL of HCl and a few drops of phenolphthalein indicator. The buret contains 0.140 M NaOH. It requires 13.5 mL of the NaOH solution to reach the endpoint of the titration. A buret filled with a titrant is held above a graduated cylinder containing an analyte solution.

What is the initial concentration of HCl?

concentration:............................M HCl

Answer 1

To calculate the initial concentration of HCl, we can use the following formula: M1V1 = M2V2 where M1 is the initial concentration of HCl, V1 is the volume of HCl used in the titration (10.0 mL), M2 is the concentration of NaOH (0.140 M), and V2 is the volume of NaOH used to reach the endpoint of the titration (13.5 mL). Rearranging the formula to solve for M1, we get: M1 = (M2V2) / V1 Substituting the given values, we get: M1 = (0.140 M)(13.5 mL) / 10.0 mL M1 = 0.189 M Therefore, the initial concentration of HCl is 0.189 M.