Acid-base titration is a fundamental analytical technique and a critical skill for every B.Pharm student. This method is essential for quantitatively determining the concentration of acidic and basic active pharmaceutical ingredients and excipients, ensuring product quality and potency. This quiz will test your understanding of titration principles, indicators, neutralization curves, and the theory behind titrating strong and weak acids and bases.
- In an acid-base titration, the point where the moles of acid are chemically equivalent to the moles of base is called the:
- End point
- Equivalence point
- Neutral point
- Indicator point
- A substance that changes color at or near the equivalence point of a titration is a(n):
- Titrant
- Analyte
- Buffer
- Indicator
- The solution of a known concentration used in a titration is the:
- Analyte
- Titrant
- Standard
- Sample
- A neutralization curve is a plot of pH versus the:
- Volume of analyte
- Volume of titrant added
- Temperature
- Concentration of indicator
- For the titration of a strong acid with a strong base, the pH at the equivalence point is:
- Less than 7
- Exactly 7
- Greater than 7
- Dependent on the indicator used
- Which of the following indicators would be most suitable for a strong acid-strong base titration?
- Phenolphthalein
- Thymol blue
- Eriochrome Black T
- Starch
- In the titration of a weak acid with a strong base, the pH at the equivalence point is:
- Less than 7
- Exactly 7
- Greater than 7
- Equal to the pKa of the acid
- Which indicator is most suitable for the titration of a weak base with a strong acid?
- Phenolphthalein (pH range 8.2-10)
- Methyl orange (pH range 3.1-4.4)
- Thymolphthalein (pH range 9.3-10.5)
- Alizarin yellow (pH range 10.1-12.0)
- The theory that states that an acid-base indicator is a weak organic acid or base whose undissociated form has a different color than its ionized form is:
- The Quinonoid Theory
- The Lewis Theory
- Ostwald’s Theory
- The Arrhenius Theory
- Why is the titration of a weak acid with a weak base generally avoided in analytical chemistry?
- The reaction does not go to completion.
- There is no suitable indicator.
- The change in pH at the equivalence point is not sharp.
- The reaction is too slow.
- The point in a titration where the indicator changes color is the:
- Equivalence point
- End point
- Half-equivalence point
- Stoichiometric point
- The solution of an unknown concentration being analyzed in a titration is the:
- Titrant
- Standard
- Indicator
- Analyte
- In the titration curve of a weak acid versus a strong base, a buffer region is formed:
- Before any base is added
- At the equivalence point
- After the equivalence point
- Before the equivalence point
- Which theory explains the color change of indicators as a result of structural changes, specifically tautomerism between benzenoid and quinonoid forms?
- Ostwald’s Theory
- Arrhenius Theory
- Brønsted-Lowry Theory
- The Quinonoid Theory
- For a good titration, the difference between the end point and the equivalence point should be:
- As large as possible
- Minimal
- Exactly one pH unit
- Equal to the pKa
- Which of the following is an example of a strong acid?
- Acetic acid (CH₃COOH)
- Carbonic acid (H₂CO₃)
- Hydrochloric acid (HCl)
- Formic acid (HCOOH)
- Which of the following is an example of a weak base?
- Sodium hydroxide (NaOH)
- Potassium hydroxide (KOH)
- Calcium hydroxide (Ca(OH)₂)
- Ammonia (NH₃)
- The steep vertical portion of a neutralization curve indicates the:
- Starting pH
- Buffer region
- Equivalence point region
- Final pH
- Phenolphthalein is colorless in acidic solutions and ______ in basic solutions.
- Yellow
- Pink
- Blue
- Orange
- At the half-equivalence point in the titration of a weak acid with a strong base, the relationship between pH and pKa is:
- pH > pKa
- pH < pKa
- pH = pKa
- pH = 7
- Which of the following pairings would result in a neutralization curve with a starting pH above 7 and an equivalence point below 7?
- Strong acid vs Strong base
- Weak acid vs Strong base
- Strong acid vs Weak base
- Weak acid vs Weak base
- The process of determining the exact concentration of a solution is called:
- Titration
- Standardization
- Neutralization
- Dilution
- Methyl orange is red in acidic solutions and ______ in basic solutions.
- Pink
- Colorless
- Blue
- Yellow
- The shape of a neutralization curve depends on:
- The temperature and pressure
- The concentrations and strengths of the acid and base
- The indicator used
- The speed of titration
- For an indicator to be suitable for a titration, its pH range of color change must overlap with the:
- Buffer region
- Steep portion of the titration curve
- Starting pH
- Final pH
- Which reaction type is the basis for acid-base titrations?
- Precipitation
- Redox
- Neutralization
- Complexation
- What happens to the pH of an acidic solution as a strong base is added during titration?
- It decreases gradually.
- It increases gradually and then rapidly near the equivalence point.
- It remains constant.
- It decreases rapidly and then gradually.
- An indicator is typically a:
- Strong acid or strong base
- Weak organic acid or weak organic base
- Neutral salt
- Non-polar solvent
- The titration of acetic acid (CH₃COOH) with sodium hydroxide (NaOH) is an example of a:
- Strong acid vs Strong base titration
- Weak acid vs Strong base titration
- Strong acid vs Weak base titration
- Weak acid vs Weak base titration
- What is the purpose of the buffer region in a weak acid titration curve?
- It shows the point of complete neutralization.
- It is a region where the pH changes very slowly upon addition of titrant.
- It indicates the end point of the titration.
- It is where the solution is most acidic.
- In the titration of a weak base with a strong acid, the solution at the equivalence point will be:
- Acidic
- Basic
- Neutral
- A buffer
- The titration error is defined as:
- The difference between the equivalence point and the end point.
- An error in reading the burette.
- An error in preparing the standard solution.
- The difference between the starting pH and the final pH.
- The titration of hydrochloric acid (HCl) with ammonia (NH₃) is a:
- Strong acid vs Strong base titration
- Weak acid vs Strong base titration
- Strong acid vs Weak base titration
- Weak acid vs Weak base titration
- According to Ostwald’s theory, the color of an indicator depends on:
- Its concentration
- The degree of its ionization
- The temperature of the solution
- Its molecular weight
- The inflection point of a titration curve corresponds to the:
- Starting point
- Equivalence point
- End point
- Half-equivalence point
- Which of these titrations would give the sharpest change in pH at the equivalence point?
- 0.1 M Acetic acid with 0.1 M Ammonia
- 0.1 M Acetic acid with 0.1 M NaOH
- 0.1 M HCl with 0.1 M NaOH
- 0.01 M HCl with 0.01 M NaOH
- For a weak acid, the undissociated form (HIn) and the ionized form (In⁻) of an indicator have:
- The same color
- Different colors
- The same structure
- No color
- A polyprotic acid will show on its titration curve:
- A single, sharp equivalence point
- No equivalence point
- Multiple equivalence points corresponding to each acidic proton
- A straight line
- In the titration of a strong acid with a weak base, which indicator is most suitable?
- Phenolphthalein
- Methyl red
- Alizarin Yellow
- Thymolphthalein
- The pH of the solution at the equivalence point of a weak acid-strong base titration is determined by the:
- Hydrolysis of the conjugate base of the weak acid.
- Hydrolysis of the conjugate acid of the strong base.
- Amount of excess base added.
- Initial concentration of the acid.
- An indicator’s useful pH range is generally considered to be:
- pKa ± 1
- pKa ± 2
- Exactly the pKa
- Any pH from 1 to 14
- What is the titrant in the assay of sodium benzoate?
- A strong acid
- A strong base
- A weak acid
- A weak base
- The equipment used to accurately deliver the titrant into the analyte solution is the:
- Beaker
- Pipette
- Burette
- Volumetric flask
- Which factor does NOT typically affect the accuracy of an acid-base titration?
- The choice of indicator
- The precision of the glassware
- The stability of the standard solution
- The color of the analyte solution
- Titration of sodium carbonate with HCl will have:
- One equivalence point
- Two equivalence points
- No equivalence point
- A straight-line curve
- The classification of acid-base titrations is based on:
- The relative strengths of the acid and base
- The solvents used
- The temperature of the reaction
- The type of indicator used
- What is the purpose of preparing a neutralization curve?
- To determine the concentration of the analyte
- To help select a suitable indicator for the titration
- To calculate the temperature change
- To measure the rate of the reaction
- In the titration of a diprotic acid like H₂SO₄ with NaOH, the first equivalence point corresponds to the neutralization of:
- Both protons
- The second proton
- Half of the first proton
- The first proton
- An ideal indicator for a titration should change color:
- As close to the equivalence point as possible
- At the beginning of the titration
- At the half-equivalence point
- After the equivalence point
- The primary chemical reaction in an acid-base titration is the formation of:
- A precipitate
- A complex ion
- Water and a salt
- A gas
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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