Check all of the following statements which are TRUE for a titration.
Select one or more:
a. A suitable primary standard must be available.
b. The concentration of the solution in the buret (the titrant) must be known before the titration is begun.
c. Titrations can only be performed for acid + base reactions.
d. The size of the aliquot added should be reduced as the end-point is approached.
e. It must be possible to use phenolphthalein as the indicator.
f. The reaction must be rapid and irreversible.
To check which statements are true for a titration, let's analyze each statement individually:
a. A suitable primary standard must be available.
True. A primary standard refers to a substance with a known and high level of purity that can be used to create a standardized solution for the titration. This is necessary to accurately determine the concentration of the analyte being titrated.
b. The concentration of the solution in the buret (the titrant) must be known before the titration is begun.
True. The titrant, which is the solution in the buret used to titrate the analyte, must have a known concentration. Without knowing the concentration, it would be impossible to calculate accurate results.
c. Titrations can only be performed for acid + base reactions.
False. Although acid-base reactions are commonly used in titrations, titrations can be performed for many other types of reactions, including redox reactions or complexation reactions.
d. The size of the aliquot added should be reduced as the endpoint is approached.
False. The size of the aliquot (the volume of analyte taken for titration) should remain consistent throughout the titration process. Changing the size of the aliquot would affect the accuracy of the results.
e. It must be possible to use phenolphthalein as the indicator.
False. Phenolphthalein is a common indicator used in acid-base titrations, but there are many other indicators that can be used depending on the type of reaction being titrated.
f. The reaction must be rapid and irreversible.
False. While a rapid and irreversible reaction can make the titration process more efficient, it is not a requirement. Titrations can be performed with relatively slower or reversible reactions as long as the endpoint can be accurately detected.
Based on the analysis, the true statements for a titration are:
- A suitable primary standard must be available.
- The concentration of the solution in the buret (the titrant) must be known before the titration is begun.