Podcast
Questions and Answers
Which statement about acid-base indicators is correct?
Which statement about acid-base indicators is correct?
- Their ions have colors that are identical to the undissociated molecule.
- They do not change color at the equivalence point of a titration.
- They are weak organic acids or bases that slightly dissociate in aqueous solutions to form colored ions. (correct)
- They are strong acids or bases that completely dissociate in aqueous solutions.
What is the purpose of a back titration technique?
What is the purpose of a back titration technique?
- To determine the concentration of a strong acid or base.
- To resolve problems encountered in direct titrations, such as slow titrations. (correct)
- To prepare a standardized solution for use in other titrations.
- To determine the concentration of an indicator solution.
In a back titration, what is the role of the standardized NaOH solution?
In a back titration, what is the role of the standardized NaOH solution?
- It is the analyte of unknown concentration.
- It is the indicator used to determine the end point.
- It is the solution being analyzed for its ascorbic acid content.
- It is the titrant of known concentration. (correct)
Which of the following is true about phenolphthalein as an indicator in acid-base titrations?
Which of the following is true about phenolphthalein as an indicator in acid-base titrations?
In the experiment for determining ascorbic acid in vitamin C tablets, what role does phenolphthalein play?
In the experiment for determining ascorbic acid in vitamin C tablets, what role does phenolphthalein play?
What is the significance of the equivalence point in an acid-base titration?
What is the significance of the equivalence point in an acid-base titration?
In an acid-base titration, what is the primary purpose of the indicator?
In an acid-base titration, what is the primary purpose of the indicator?
In the context of the back titration technique, what is the role of the standardized NaOH solution?
In the context of the back titration technique, what is the role of the standardized NaOH solution?
Which of the following statements accurately describes the relationship between the end point and the equivalence point in an acid-base titration?
Which of the following statements accurately describes the relationship between the end point and the equivalence point in an acid-base titration?
According to the Brønsted-Lowry theory, which of the following statements is true about weak acids and bases?
According to the Brønsted-Lowry theory, which of the following statements is true about weak acids and bases?
In the experiment for determining ascorbic acid (Vitamin C) in tablets, what is the role of phenolphthalein as the indicator?
In the experiment for determining ascorbic acid (Vitamin C) in tablets, what is the role of phenolphthalein as the indicator?
Which of the following statements accurately describes the role of the titrant in an acid-base titration?
Which of the following statements accurately describes the role of the titrant in an acid-base titration?
In the context of acid-base titrations, what is the primary purpose of performing a back titration?
In the context of acid-base titrations, what is the primary purpose of performing a back titration?
According to the definition provided, which of the following statements accurately describes the analyte in an acid-base titration?
According to the definition provided, which of the following statements accurately describes the analyte in an acid-base titration?
Which of the following statements accurately describes the role of a strong acid or base in an acid-base titration?
Which of the following statements accurately describes the role of a strong acid or base in an acid-base titration?
In the context of acid-base indicators, what is the significance of the color change observed at the end point?
In the context of acid-base indicators, what is the significance of the color change observed at the end point?
Study Notes
Titration
- A technique used to determine the concentration of an identified analyte by reacting it with a solution of known concentration (titrant)
- Involves adding a solution of known concentration from a burette to a measured volume of analyte
Analyte and Titrant
- Analyte: a solution of unknown concentration (known volume)
- Titrant: a solution of known concentration (volume obtained by titration)
Equivalence Point and End Point
- Equivalence point: the point at which the moles of added titrant are stoichiometrically equal to the moles of analyte
- End point: signals the end of titration where the indicator gives an observable change, located very close to the equivalence point
Acid-Base Chemistry
- Acid: a proton (H+) donor (Bronsted-Lowry definition)
- Base: a proton (H+) acceptor (Bronsted-Lowry definition)
- Strong acid/base: completely dissociates with water
- Weak acid/base: partially dissociates with water
Acid-Base Indicators
- Weak organic acids or bases that dissociate slightly in aqueous solutions to form ions
- Indicators change colors because their ions have colors that are different from undissociated molecules
- Example: phenolphthalein, a weak acid that is colorless in acidic and neutral solutions and pink in basic solutions
Acid-Base Titration
- A procedure used in quantitative analysis to determine the concentration of either an acid or a base
- Indicator should change sharply at the equivalence point
- At the end point of titration, all acids and bases are neutralized, and the flask contains water and salt only
Back Titration
- An alternative technique to direct titration designed to resolve some problems encountered in direct titration, such as slow titration
- Titrant: standardized NaOH solution
- Analyte: ascorbic acid (Vitamin C tablet samples)
- Indicator: phenolphthalein
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Description
This quiz covers the definition and key concepts of titration technique, where a solution of known concentration is used to determine the concentration of an unknown analyte. It includes information on analyte, titrant, equivalence point, and end point.
