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In acidic medium, the equivalence point can be detected using an acid-base indicator that undergoes a color change at the pH corresponding to the equivalence point. Alternatively, a pH meter can be used to monitor the pH of the solution during the titration, with the equivalence point identified as the point of maximum change in pH.
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Consider the titration of 30.0 ml of 0.030 M NH3 with 0.025 M HCl the equivalence point is reached when 36 ml of HCl titrant is added what is the pH at the equivalence point?
At the equivalence point, all ammonia (NH3) is converted to ammonium ion (NH4+). The solution contains ammonium chloride (NH4Cl), a salt of a weak acid (NH4+) and a strong acid (Cl-), making the solution acidic. The ammonium ion hydrolyzes in water to form NH4+ + H2O -> NH3 + H3O+. Therefore, the pH at the equivalence point will be less than 7, indicating an acidic solution.
How can the equivalence point in a titration be detected by using a pH meter?
The pH meter can detect the equivalence point in a titration by monitoring a sudden change in pH value. At the equivalence point, the number of moles of acid and base are equal, causing a rapid increase or decrease in pH depending on the reaction. This abrupt change marks the completion of the reaction and helps determine the exact volume of titrant needed to reach the equivalence point.
A titration of an acid and base to the equivalence point results in a noticeably acidic solution It is likely this titration involves?
a weak acid and strong base. At the equivalence point of a titration between a weak acid and a strong base, the resulting solution will have a pH greater than 7, indicating a basic solution. For the solution to be noticeably acidic at the equivalence point, it would suggest an excess of the weak acid after the reaction, which means that the acid is likely weak and not completely neutralized by the strong base.
Why isn't the pH at the equivalence point always equal to 7 in a neutralization titration?
The pH at the equivalence point may not always be 7 in a neutralization titration because the nature of the acid and base being titrated can affect the pH. For example, if a strong acid is titrated with a weak base, the equivalence point may be acidic (pH < 7) due to the excess of the strong acid present. Conversely, if a strong base is titrated with a weak acid, the equivalence point may be basic (pH > 7) due to the excess of the strong base.
What is electrometric titration?
Electrometric titration is a method of determining the concentration of a specific ion in a solution by measuring changes in electrical potential. It involves using an electrode pair to detect the equivalence point of a chemical reaction based on changes in voltage. This technique is commonly used in analytical chemistry to measure acidic or basic components in a sample.
Standardising HCl using Na2CO3 titration. textbook says the solution at the equivalence point is slightly acidic. is it and why?
Yes, the solution at the equivalence point of titrating HCl with Na2CO3 is slightly acidic. This is because a weak acid, H2CO3, is formed in addition to NaCl. The carbonic acid (H2CO3) contributes to the slight acidity of the solution.
What is the relationship of the successive equivalence point volumes in the titration of polyprotic acid?
the end point will be a simple multiple of the first
What is the relationship of the successive equivalence-point volumes in the titration of a polyprotic acid?
In the titration of a polyprotic acid, the successive equivalence-point volumes decrease because each equivalence point corresponds to the complete neutralization of one acidic proton. This leads to a decrease in the moles of acid present in the solution, requiring less titrant to reach the subsequent equivalence points.
Consider the titration of 30.0 ml of 0.030 M NH3 with 0.025 M HCl the equivalence point is reached when 36 ml of HCl titrant is added what is the pH at the equivalence point?
At the equivalence point, all ammonia (NH3) is converted to ammonium ion (NH4+). The solution contains ammonium chloride (NH4Cl), a salt of a weak acid (NH4+) and a strong acid (Cl-), making the solution acidic. The ammonium ion hydrolyzes in water to form NH4+ + H2O -> NH3 + H3O+. Therefore, the pH at the equivalence point will be less than 7, indicating an acidic solution.
How can the equivalence point in a titration be detected by using a pH meter?
The pH meter can detect the equivalence point in a titration by monitoring a sudden change in pH value. At the equivalence point, the number of moles of acid and base are equal, causing a rapid increase or decrease in pH depending on the reaction. This abrupt change marks the completion of the reaction and helps determine the exact volume of titrant needed to reach the equivalence point.
Why would phenolpthalein not be a suitable indicator for the standardisation of hydrochloric acid with Borax?
Phenolphthalein is not suitable for titration involving Borax and hydrochloric acid because it changes color at a pH lower (usually around pH 8-9) than the equivalence point of this specific titration. Borax reacts as a weak base while hydrochloric acid is a strong acid, making the equivalence point acidic in nature. A suitable indicator would need to change color near this acidic pH of the equivalence point.
A titration of an acid and base to the equivalence point results in a noticeably acidic solution It is likely this titration involves?
a weak acid and strong base. At the equivalence point of a titration between a weak acid and a strong base, the resulting solution will have a pH greater than 7, indicating a basic solution. For the solution to be noticeably acidic at the equivalence point, it would suggest an excess of the weak acid after the reaction, which means that the acid is likely weak and not completely neutralized by the strong base.
Why isn't the pH at the equivalence point always equal to 7 in a neutralization titration?
The pH at the equivalence point may not always be 7 in a neutralization titration because the nature of the acid and base being titrated can affect the pH. For example, if a strong acid is titrated with a weak base, the equivalence point may be acidic (pH < 7) due to the excess of the strong acid present. Conversely, if a strong base is titrated with a weak acid, the equivalence point may be basic (pH > 7) due to the excess of the strong base.
What is the difference between the end point and the equivalence point?
The equivalence point is the point in a titration when the amount of added standard reagent is chemically equal to the amount of analyte. The end point is the point in a titration when a physical change occurring immediate after the equivalence point
Why titration of weak acid and weak base are not done?
Titration of weak acid and weak base is not typically performed because the equivalence point is difficult to determine due to the buffering capacity of the solution at the equivalence point. The pH at the equivalence point for weak acid and weak base titrations may not be close to 7, making it challenging to accurately detect the endpoint.
What is electrometric titration?
Electrometric titration is a method of determining the concentration of a specific ion in a solution by measuring changes in electrical potential. It involves using an electrode pair to detect the equivalence point of a chemical reaction based on changes in voltage. This technique is commonly used in analytical chemistry to measure acidic or basic components in a sample.
Is equivalence point PKa?
No, the equivalence point is not the same as pKa. The equivalence point is the point in a titration where the moles of acid are stoichiometrically equal to the moles of base, while pKa is a measure of the strength of an acid and its tendency to donate a proton.
