Question

Measuring molarity of an ionic solution can be accomplished utilizing numerous methods.
Which of the following is the least accurate method for the solution described?

• A. Titration of an unknown base solution with a known concentration of an acid using phenolphthalein as an indicator.
• B. Evaporation of a known volume of a salt solution with final massing of the remaining dried solid.
• C. Use of a conductivity meter to determine the presence of relative amounts of ions in three different solutions.
• D. Taking the mass of a known volume of an ethanol and water solution to determine the density of the solution.

Answer 1

The correct option is A Titration of an unknown base solution with a known concentration of an acid using phenolphthalein as an indicator.

Phenolpthalein is an basic indicator. So, it is not best method to titrate an unknown basic solution using known concentration of acid.