(DA) Feb 28, 2011: Titrations

• A titration is an experimental technique used to determine the concentration of an unknown solution

Terms & Equipment

• Buret - contains the known solution. Used measure how much is added
• Stopcock - Valve used to control the flow of solution from the buret
• Pipet - Used to accurately measure the volume of unknown solution
• Erlenmeyer Flask - Container for unknown solution
• Indicator - Used to identify the end point of the titration
• Stock Solution - Known solution

Example

• Jon the chemist wants to determine the concentration of a Sodium Hydroxide sample so he does a titration with HCl. He gathers the following data. Determine [NaOH]

NaOH sample = 10.00 mL                      [HCl] = 0.75M

Trial                              1                             2                          3                        4
Final Reading (mL)      13.3                        26.0                     38.8                  13.4
Initial Reading (mL)       0.2                        13.3                     26.0                   0.60
Volume Used (mL)      13.1                        12.7                     12.8                  12.8
                                                                                                          Vaverage = 12.85 mL


0.75 mol x 0.01285 L x 1 = 0.0964 mol
      L                             1

0.0964 mol x 1     = 0.964 mol/L
                 0.010L