What is the role of an indicator in an acid-base titration? Identify how an appropriate indicator...
Question:
What is the role of an indicator in acid-base titration? Identify how an appropriate indicator is chosen and use the terms "endpoint" and "equivalence point" to explain how an indicator works.
Indicators:
Indicators are chemical species that show a color change when there is a change in the pH of the solution. They are usually weak acids or bases whose conjugate acid or base when formed, shows a drastic color change.
Answer and Explanation: 1
Become a Study.com member to unlock this answer! Create your account
View this answerIn an acid-base titration, a neutralization reaction is taking place. This indicates the formation of salt and water. An indicator is added to...
See full answer below.
Ask a question
Our experts can answer your tough homework and study questions.
Ask a question Ask a questionSearch Answers
Learn more about this topic:

from
Chapter 11 / Lesson 11Learn about acid-base indicators. Understand what acid-base indicators are, how they work to determine if a solution is acidic or basic, and see the examples.
Related to this Question
- (a) What is the role of an indicator in an acid-base titration? (b) How an appropriate indicator is chosen? (c) Explain how an indicator works.
- a) What is an acid-base indicator? b) Define the equivalence (stoichiometric) point and the endpoint of a titration. Why should you choose an indicator so that the two points coincide? c) Do the pH values of the two points have to be within \pm 0.01 pH
- What is the role of an indicator in an acid-base titration?
- In acid base titration, how does an indicator work?
- The correct indicator for a given titration system depends on the strength of the acid being titrated. How could we determine the strength of the acid in order to pick an appropriate indicator (i.e. an indicator that is weaker than the acid)?
- Describe three characteristics of a good acid-base indicator for a particular titration.
- 1. What is the difference between equivalence point and endpoint? 2. In a titration with a strong acid and a strong base, why used phenolphthalein as the indicator? 3. If the color remains clear, th
- 1. What is a primary standard substance? Give an example. 2. What is meant by the term, equivalence point, during an acid-base titration? 3. What is an indicator? What role does it play in an acid-b
- Indicators are widely used in acid-base titrations. Explain the use of indicators.
- What is the role of an acid-base indicator?
- Give the structure for an acid-base indicator. It can be any acid-base indicator, except phenolphthalein. Explain how an acid-base indicator works (why it changes color when it does). Give the chemical reaction(s) that shows why the color changes in your
- Why was phenolphthalein a good indicator to use for determining the equivalence point between the unknown weak acid and strong base?
- An indicator with a value of PKln is not suitable for the titration of a weak base versus a strong acid. Explain.
- 1. Explain the chemical information that can be determined about an acid using the equivalence point and half-equivalence point of a titration curve. 2. Describe when you can use the Henderson- Hasse
- Provide definitions for the following terms: a. Neutralization. b. acid-base indicator. c. volumetric titration.
- Describe the meaning of each in terms of its application to acid base titrations. a) standardization b) indicator c) endpoint
- Distinguish between a stoichiometric point and an endpoint in an acid-base titration.
- How does an acid-base indicator function?
- In an acid/base titration, why must the indicator (phenolphthalein) be a strong dye?
- What is acid base titration? What is alkalimetry and acidimetry? Discuss the methods in acid base titration, titration of weak acid and base.
- Suggest an indicator, other than phenolphthalein, that would be suitable for weak acid/strong base and weak base/strong acid titration. Explain why it would be effective?
- How can we determine the equivalence point (or endpoint) in the curves in titration (strong acid/weak base and weak acid/strong base)?
- Explain why acid-base titration is a useful technique in chemistry.
- Distinguish between the following pairs of terms as they pertain to this experiment. a. monoprotic and diprotic acids b. equivalence point and end point of a titration c. half-equivalence point and
- The amount of indicator used in an acid-base titration must be small. True False Explain.
- In an acid-base titration, how would you monitor the progress of the experiment and know when it was completed? What observation would indicate a reaction has begun?
- What is an acid/base indicator?
- Which of the pH indicators from the following would be most appropriate for the titration of 0.30 M hydroxylamine (K_b = 9.1 x 10^{-9}) with 0.15 M hydrochloric acid? A) Methyl orange. B) Litmus. C) Thymol blue. D) trinitrobenzene. E) None.
- Circle which one of the following indicators you would select for a titration of a strong acid against a strong base. (i) Phenolphthalein (pH range 8.3 - 10.0, colourless \rightarrow pink) (ii) Phenol red (pH range 4.4 - 6.2, red \rightarrow yellow) (iii)
- At the equivalence point of an experiment where a strong acid is titrated using a strong base, which of the following statements is/are true? Select as many as appropriate. A) number of moles of acid initially = number of moles of base added B) Phenolphth
- What determines the color of an acid-base indicator in an aqueous solution?
- Discuss the equivalence point. What does it mean in terms of acid/base equilibrium?
- When choosing a suitable indicator for a titration between a strong acid and a weak base, the indicator should change color in the pH range of: a) exactly 7 b) less than 7(slightly acidic) c) greater than 7(slightly basic) d) near 14(very basic)
- Why don't indicators in acid-base reactions influence the pH of the solution?
- Which indicator is best suited for the titration of 0.05 M HOCl (pK_a = 7.54) with 0.05 M NaOH? 1) Thymolphthalein (pK_{HIn} = 9.85). 2) Methyl red (pK_{HIn} = 5.30). 3) Phenol red (pK_{HIn} = 7.60). 4) Bromophenol blue (pK_{HIn} = 3.80). 5) Alizarin yel
- How does an acid - base indicator such as methyl orange work in a system at equilibrium? What is the dominant species of the indicator when the solution is acid or base?
- Which of the following conditions is true for a titration of a strong acid with a weak base? a. The equivalence point occurs at a pH greater than 7. b. The equivalence point occurs at a pH equal to 7. c. The equivalence point occurs at a pH below 7. d. Eq
- 1. How does the titration of a diprotic acid differ from a monoprotic acid (like HF)? 2. How does the titration of a weak base with a strong acid differ from weak acid-strong base titration. (Review
- Why is the equivalence point of a weak acid-strong base titration above 7.0?
- What are the chemical and physical properties of litmus? What allows it the ability to act as an acid-base indicator?
- Phenolphthalein indicator is often used for HCl/NaOH titrations. The indicator turns faint pink with the first drop of excess base. Which statement(s) correctly explains this behavior? (choose all that apply) A. The acidic form of phenolphthalein does not
- Is the titration of HNO3 with dimethylamine an example of the titration of a strong acid with a weak base? Explain.
- Explain why monoprotic acidic salts behave as strong enough acids to be titratable with NaOH using phenolphthalein as an indicator?
- For the acid/base titration of HNO3 and CH3NH2, choose a suitable indicator from the list below. Beside each indicator, the pH range of colour change at its endpoint is provided. (a) methyl orange (3.1 - 4.4) (b) bromothymol (6.0 - 7.7) (c) thymolphthalei
- What is an acid-base indicator and how is it used in a liquid-liquid extraction?
- In titration of a weak base with strong acid to determine the value of K_b
- What are the similarities and differences between redox titration and acid-base titration?
- 6 (H+) + 2(MnO4-) + 5(H2O2) \longrightarrow 5(O2) + 8(H2O) + 2(Mn)2+ Using the information below, explain why it is important to do the titration in an acidic solution rather than a neutral or basic solution. (Hint: Consider your ability to judge the e
- What is acid base titration?
- Why would phenolphthalein be used to detect the end point of a neutralization reaction?
- What are the essential characteristics of acid-base indicators?
- Choose all the true statements about the equivalence point in an acid-base titration curve. A. It occurs when stoichiometric amounts of acid and base have reacted. B. It occurs when equal volumes of a
- Discuss briefly the titration of acids and bases and the methods used to determine the rate of reaction.
- Discuss the methods in acid-base titration.
- What advantage is there to testing a solution with pH paper versus using an acid/base indicator?
- Describe the apparent relationship between H_3O and OH concentrations when an endpoint is reached in acid-base titration.
- Which best describes the pH at the equivalence point of a titration of a weak base with a strong acid? A. less than zero B. between 0 and 7 C. close to 7.0 D. between 7 and 14 E. greater than 14
- Which best describes the pH at the equivalence point of a titration of a weak acid with a strong base? A. less than zero B. between 0 and 7 C. close to 7.0 D. between 7 and 14 E. greater than 14
- The colours of the acid and base forms of the indicator Bromo cresol green are yellow and blue, respectively, and its pK_a is 4.6. (a) What colour would be expected for the indicator in a solution of pH 6.0 and in a solution of pH 4.8?
- Is it possible to determine the Ka of a weak acid at points other than the halfway point of a titration? Explain.
- Which of the following are true regarding a Gran Plot? Select all that are appropriate. (a) The equivalence point of the titration is represented by the y-intercept. (b) The slope of the plot depends on Ka for the acid being titrated. (c) Results in a str
- Which of the following acid-base indicators should be used for the titration of NH3 with HBr? Kb of ammonia is 1.8 x 10^{-5}. 1. Methyl red, color change red/yellow at 4.4 less than pH less than 6.2 2. Any of these is suitable. 3. Neutral red, color ch
- 1. Define the following terms: *weak acid *strong base *equivalence point *primary standard 2. A sample of acetic acid (weak acid) was neutralized with 0.05 M NaOH solution by titration. 34 mL of NaOH had been used. CH_3COOH + NaOH --> CH COONa + H_2O a
- What is the color of a phenolphthalein indicator in an acidic solution?
- List the species present in solution during titration of a strong acid and a strong base: Equivalence point
- Answer the following statement, and explain your answer. It is always true that the equivalence point of a standard weak acid/strong base titration is: A) When the pH = 7.00 B) Reached when all of the weak acid has been converted into its conjugate wea
- Methyl red has the following structure: What is the color change and the pH at the color change when a weak base is titrated with a strong acid using methyl red as an indicator? For which of these two types of titrations is methyl red a possible indicator
- What other acid indicators are there other than phenolphthalein? Are there any better indicators than phenolphthalein?
- Define a base in terms of its properties? Then try to expand upon this definition in interpreting its role in an acid-base reaction.
- Choose the correct classification for SO3^2-(aq). a. Polyprotic base b. Polyprotic acid c. Monoprotic acid d. Monoprotic base
- Which of the following is true about indicators? A. They are weak acids or bases. B. They are as accurate as a pH meter. C. They maintain their colors across the range of pH values for which they a
- Which indicators would be most suitable for the titration of 0.10 M lactic acid with 0.10 M KOH(aq)? For lactic acid, pKa = 3.08.
- Identify as an acid or a base. Provide a chemical equation showing how this is an acid or a base according to the Arrhenius definition. a) Sr(OH)_2 (aq) b) HBr (aq) c) NaOH (aq)
- Based on the steps occurring in an acid-base reaction, what definition of acids and bases is most practical? Give three reasons for your choice.
- Which of the following indicators would be most suitable for the titration of 0.1 M lactic acid with 0.10 M KOH(aq)? For lactic acid, pKa = 3.08. (a) thymol blue (pKin = 1.7) (b) phenol red (pKin = 7.9) (c) alizarin yellow (pKin = 11.2) (d) methyl orange
- Acid base indications usually show a colour change: a. at exactly the pKin of the indicator b. generally over the range pKin +/- 1 c. at exactly pH =7
- Phenolphthalein is an acid-base indicator. a. What color does it possess in the presence of excess hydrogen (i.e., hydronium) ions? b. What color does it possess in the presence of excess hydroxide ions? c. What color would you expect phenolphthalein to b
- Litmus paper is a classic pH indicator. a.Describe the color change litmus paper undergoes when placed in both acidic and basic solutions? b. For Litmus paper, the color change is over the pH range of____________ to ____________.
- Why do we need acid-base indicators that change at pH values other than 7?
- Choose the correct classification for HSO3-(aq). a. Polyprotic base b. Polyprotic acid c. Monoprotic acid d. Monoprotic base
- How do you predict if a solution is acidic or basic? Explain using examples from this experiment. How do structural properties affect the strengths of acids and bases? What happens when a strong acid
- What are the expected differences that should be observed for titration of a strong acid, weak acid, and polyprotic acid with a strong base like NaOH (aq)?
- An acid turns the indicator litmus to what color?
- Sketch two pH curves, one for the titration of a weak acid with a strong base, and one for the titration of a strong acid with a strong base. How are they similar? How are they different? Account for the similarities and the differences.
- List the species present in solution during titration of a strong acid and a strong base: At the half-equivalence point.
- When titrating a weak base with a strong acid, what effect will washing the tip of the burette and sides of the beaker with distilled water have on the pKa and equivalence points?
- An acid base indicator like bromocresol green is blue under basic conditions and yellow under acidic conditions. What would be a good methodology to quantify a substance of this sort which has general equilibrium as followed: H_2O + Hln \leftrightarrow
- ||Indicator||Color of acid form||Color of base form||Ka value |'A'|red|yellow|1.0 x 10¯³ |'B'|yellow|blue|1.0 x 10¯⁹ What are the predominant colors of each indicator at pH 7?
- List the species present in solution during titration of a weak acid and a strong base: Half Equivalence Point.
- Match the statement with the type of titration: 1. strong acid-strong base 2. weak acid-strong base 3. strong acid-weak base it would apply to. Titration types can be used more than once or not at all. (a) Endpoint/Equivalence point pH is basic. (b) Endpo
- What will be the effect of a weak acid in a back titration using a strong base?
- How is the strength of a weak acid or a weak base determined? Explain how the pH of the salt of a weak acid may be determined.
- Using the Bronsted-Lowry definition of acids and bases, identify each reactant in the reactions below as an acid or base. Explain how you determined your answers. a. H3O+ + Cl- arrow H2O + HCl b. H2PO4- + H2O arrow H3O+ + HPO42- c. HSO4- + H2O arrow OH- +
- How do you identify an acid-base reaction? Give an example.
- Sketch a titration curve of a monoprotic acid and dioprotic acid titrated with a strong base, labeling the equivalence point. In addition label where the solution is a) acidic b) basic c) contains mostly acid with some conjugate base and d) contains only
- Consider the titration of a generic weak acid HA with a strong base that gives the following titration curve: On the curve indicate the points that correspond to the following. a. the equivalence point b. the maximum buffering region c. pH = pKa d. pH dep
- Choose the correct classification for HCOOH(aq). a. Polyprotic base b. Polyprotic acid c. Monoprotic acid d. Monoprotic base
- What does the color indicate about the strength of an acid or base?
- List the species present in solution during titration of a weak acid and a strong base: Equivalence Point.