Questions and Answers
What is the principle of conductometric titrations?
During a titration process, one ion is replaced with another and the difference in the ionic conductivities of these ions directly impacts the overall electrolytic conductivity of the solution.
How can the end point of conductometric titration be determined?
By means of conductivity measurement.
What happens to conductivity when a base is added to a strong acid during titration?
What occurs at the equivalence point in a conductometric titration of strong acid against strong base?
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In the titration of weak acid (CH3COOH) against strong base (NaOH), what happens to conductivity after the equivalence point?
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In the titration of strong acid against weak base, the initial conductivity decreases due to the replacement of fast moving ions with slower moving ones.
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The reaction in weak acid against weak base titration can produce ______ as a salt.
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Study Notes
Conductometric Titrations
- Conductometric titrations utilize the principle that ionic conductivities vary between different ions, impacting the overall electrolytic conductivity of the solution during a titration.
- Conductivity variations are influenced by the type of ions present, the occurrence of chemical reactions, and the concentration of ionic entities.
- The main objective is to determine the equivalence point through conductivity measurements, particularly in acid-base neutralization reactions.
Principle and Theory
- In a titration, one ion replaces another, affecting solution conductivity.
- Initial addition of a base to an acid results in a decrease in conductivity as H+ ions are substituted by the slower-moving ions of the base.
- Following the equivalence point, conductance increases due to a higher concentration of fast-moving ions in the solution.
- Conductometric titration plots exhibit two intersecting lines with opposite slopes marking the equivalence point.
Strong Acid vs. Strong Base (HCl against NaOH)
- HCl in a conductivity vessel and NaOH in a burette are used for measurement.
- Conductance decreases initially as H+ ions are replaced by slower Na+ ions during neutralization.
- After reaching the equivalence point, introduction of fast-moving OH- ions increases the conductance.
- The plot of conductance versus volume of NaOH reveals two lines intersecting at point ‘B’, indicating the end-point of the titration.
Weak Acid vs. Strong Base (CH3COOH against NaOH)
- Weak acids exhibit low conductance; adding a strong base converts poorly conducting acid to highly ionized salt, slowly increasing conductance until equivalence.
- Beyond the equivalence point, excess hydroxide ions lead to a sharp conductance increase.
- The graph depicts gradual increase until point ‘B’ where a significant rise occurs thereafter.
Strong Acid vs. Weak Base (HCl against NH4OH)
- Initial conductance decrease occurs due to H+ ions being replaced by slower NH4+ ions.
- Additional weak base doesn’t significantly alter conductance post-equivalence.
- The intersection of curves denotes the titration end-point.
Weak Acid vs. Weak Base (CH3COOH against NH4OH)
- Conductance initially increases due to strong electrolyte formation (CH3COONH4).
- Increase continues until the equivalence point, after which conductance stabilizes with minimal changes.
- The change represents completion of the reaction as a salt is formed.
Graphical Representation
- Graphs illustrate the change in conductance through various titrations, characterized by segments where conductance increases or decreases, culminating in a sharp transition at equivalence points.
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Description
Explore the principles of conductometric titrations in this quiz. Understand how ionic conductivities affect the electrolytic conductivity of solutions during the titration process. Test your knowledge of electrochemistry concepts in a concise format.
