In conductometric titration, conductance increases after the endpoint because, beyond this point, excess titrant ions enter the solution, contributing to a higher ionic concentration. As the reaction between the titrant and analyte is complete, the remaining titrant ions, which are typically more conductive than the analyte ions, dominate the solution's conductivity. This results in a measurable increase in conductance, indicating that the titration has surpassed the equivalence point.
Weak Acid with a Strong Base, e.g. acetic acid with NaOH: Initially the conductance is low due to the feeble ionization of acetic acid. On the addition of base, there is decrease in conductance not only due to the replacement of H+ by Na+ but also suppresses the dissociation of acetic acid due to common ion acetate. But very soon, the conductance increases on adding NaOH as NaOH neutralizes the un-dissociated CH3COOH to CH3COONa which is the strong electrolyte. This increase in conductance continues raise up to the equivalence point. The graph near the equivalence point is curved due the hydrolysis of salt CH3COONa. Beyond the equivalence point, conductance increases more rapidly with the addition of NaOH due to the highly conducting OH− ions
The method used most often in chemistry labs is by use of a pH indicator in the sample being titrated. When you reach the titration point, the indicator will change colors, demonstrating the end point of the titration.
It is the equivalence point.
The equivalence point represents a region where the amount of acid to base (or base to acid) concentration is equal. Before the equivalence point there is a greater amount of acid (or base, depending on the titration). After the titration there is a greater amount of base (or acid). This reverse in dominance results in a dramatic change in pH.
Adding ammonium thiocyanate prior to the end point in a titration helps to detect the endpoint as it forms a red color complex with the metal ion being titrated. This complex formation signals the approach of the endpoint and allows for a more precise determination of the equivalence point in the titration.
Conductance can increase after the end point in conductometric titrations due to the presence of excess titrant in the solution, leading to higher conductivity. This excess titrant can contribute to the conductance of the solution and cause an increase in measured conductance. Factors such as incomplete reaction or side reactions can also contribute to the increase in conductance post-end point.
Conductometric titration is a method of titration where the end point is determined by measuring the change in electrical conductivity of the solution being titrated. It is commonly used to determine the concentration of ions in a solution.
The principle of conductometric titration involves measuring the change in electrical conductivity of a solution as a titrant is added to a sample solution. This change in conductivity occurs due to the formation or consumption of ions during the titration process, which can be used to determine the endpoint of the titration. Conductometric titration is commonly used to determine the concentration of ions in a solution or to identify the equivalence point in acid-base titrations.
Some types of conductometric titrations include acid-base titrations, redox titrations, and precipitation titrations. Conductometric titration involves measuring the change in electrical conductivity as reactants are titrated against each other until an equivalence point is reached.
Conductometric titration is used in analytical chemistry to determine the endpoint of a titration by monitoring changes in electrical conductivity. It is commonly used to determine the concentration of ions in a solution, such as the determination of the calcium ion concentration in water or the acid content in a sample. Conductometric titration is also useful in studying complexation reactions and acid-base titrations.
Conductometric titration is advantageous over volumetric titration as it does not require a colour change indicator, making it suitable for titrating solutions that are not easily detectable by color change. It also allows for the detection of the endpoint precisely by monitoring the conductivity change in the solution, resulting in a more accurate determination of the equivalence point. Additionally, conductometric titration can be used to analyze non-aqueous solutions and solutions with low concentrations.
In conductometric titration of a strong acid with a strong base, as the base is added to the acid solution, the conductivity of the solution increases due to the formation of ions. The inflection point of the titration curve corresponds to the stoichiometric equivalence point, where all the acid has been neutralized by the base. The conductivity then remains constant beyond this point, indicating excess of the base.
Conductance titration works on the principle of ohm's law. If we are to find the strength of a acid then we take that acid into a beaker and dip the electrode of conductometer into the acid solution. This measures the conductance of acid. Now, we titrate this acid solution against the base of known molarity, the conductance starts decreasing. This is due to the binding of H+ ions of acid with the OH- of Base until a point is reached where conductance is minimum. When we move forward the conductance starts increasing again. This is now due to the free ions of Base present in solution. The conductance produced by an ion is proportional to its concentration (at constant temperature),
1. this method can be used with very diluted solutions=2. this method can be used with colored or turbid solutions in which end point can not== be seen by eye==3. this method can be used in which there is no suitable indicator==4.has many applications , i.e. it can be used for acid base , redox ,precipitation, or complex titrations=
Weak Acid with a Strong Base, e.g. acetic acid with NaOH: Initially the conductance is low due to the feeble ionization of acetic acid. On the addition of base, there is decrease in conductance not only due to the replacement of H+ by Na+ but also suppresses the dissociation of acetic acid due to common ion acetate. But very soon, the conductance increases on adding NaOH as NaOH neutralizes the un-dissociated CH3COOH to CH3COONa which is the strong electrolyte. This increase in conductance continues raise up to the equivalence point. The graph near the equivalence point is curved due the hydrolysis of salt CH3COONa. Beyond the equivalence point, conductance increases more rapidly with the addition of NaOH due to the highly conducting OH− ions
Oxalic acid is used in conductometric titrations because it is a strong electrolyte that dissociates completely in solution, leading to a sharp increase in conductivity at the equivalence point. This makes it easier to accurately determine the endpoint of the titration.
Coductometric titration: is based on the suddenly change of the conductivity at the equivalence point.Volumetric titration: the volume of a standardized titrant is measured at the eqivalence point.