Question

Procedure for titrating an acid against a standard solution of NaOH. The acid-base indicator, phenolphthalein, is colorless in acidic solution but takes on a pink color in basic solution. How would the volume of standard solution added change if that solution were Ba(OH)2(aq) instead of NaOH(aq)?

Answer 1

volume of
`Ba(OH)_(2)` solution required will be half the volume required for NaOH solution.

Step-by-step explanation:

• NaOH is a monoacidic strong base because it produces one
  `OH^(-)` ion upon complete dissociation
• 
  `Ba(OH)_(2)` is a diacidic strong base because it produces two
  `OH^(-)` ions upon complete dissociation
• So, one molecule of NaOH neutralizes one
  `H^(+)` ion. But one molecule of
  `Ba(OH)_(2)` neutralizes two
  `H^(+)` ions.
• Hence, for similar concentrations of NaOH and
  `Ba(OH)_(2)`, volume of
  `Ba(OH)_(2)` solution required will be half of the volume required for NaOH solution.