What is the relationship between the titration endpoint and the reaction endpoint?

The reaction endpoint is the completion of the reaction, and the titration endpoint is the point at which the indicator changes color.

Take the acid-base reaction as an example: the reaction endpoint should be the system pH = 7

The titration endpoint is related to the selected indicator, such as phenolphthalein.

The discoloration range is in the pH = range

In titration analysis, when titration to the stoichiometric point, there is often no obvious external feature to judge, often with the help of the color change of the indicator to determine the termination of the titration, at this time the discoloration point of the indicator is the titration endpoint.

The titration endpoint can also be based on the potential and conductivity of the titration system.

and absorbance. This requires the help of instruments.

Acid-base titration curves.

The acid-base titration curve refers to the relationship between the pH of the solution and the volume of the titrant during the titration process. The titration curve can be determined with the help of an acidity meter.

It can also be measured by other analytical instruments by way of calculation.

Titration jumps. The sharp change in pH in the range before and after the stoichiometric point is called the acid-base titration jump. This abrupt change the solution from acidic to alkaline, and the properties of the solution change from quantitative to qualitative.

Titration error. The titration endpoint and the stoichiometric point do not necessarily coincide exactly, and there is often a certain difference, which is called the titration error or endpoint error.

Indicator selection.

Acid-base indicator.

can be neutralized in the reaction.

There is a color change at the endpoint, so the appropriate indicator must be selected for the endpoint.

In order to accurately judge the titration endpoint, it is necessary to select an acid-base indicator with obvious discoloration, and the pH of the discoloration range is consistent with the pH at the time of neutralization.

The narrower the discoloration range of the indicator, the better, and the indicator can change color with a slight change in pH. Litmus.

The solution has a wide range of discoloration.

1.What is the relationship between the titration endpoint and the reaction endpoint? The reaction endpoint is the completion of the reaction, and the titration endpoint is the point at which the indicator changes color.

Take acid-base reaction as an example: the reaction end point should be the system pH = 7 and the titration end point is related to the selected indicator, such as: phenolphthalein discoloration range in pH = titration analysis, when titration to the stoichiometric point, there is often no obvious external characteristics to judge, often with the help of the color change of the indicator to determine the termination of the titration, at this time the color change point of the indicator, is the titration endpoint.

The titration endpoint can also be judged by changes in potential, conductance, and absorbance in the titration system, which requires the help of an instrument. Acid-base titration curve The acid-base titration curve refers to the relationship curve of the pH of the solution with the volume of titrant during the titration process. Titration curves can be measured with the help of an acidity meter or other analytical instrument, or they can be calculated as a result.

Titration Leap The sudden change in pH in the range before and after the stoichiometric point is called the acid-base titration jump.

In chemical experiments, the titration endpoint and the reaction endpoint are two different stages, the titration endpoint is the addition of as many chemicals, and the reaction endpoint is that the added species have reacted.

The titration endpoint depends on the indicator used, and the pH is not necessarily equal to 7. The endpoint of the reaction refers to the completion of the reaction, depending on whether it is a neutralization reaction or metathesis, etc., and it is not necessarily equal to 7. Hope.

Other. The pH reaction endpoint is the theoretical equivalence point of the acid-base reaction, and pH is not necessarily equal to 7.

The pH titration endpoint is the point at which the indicator changes color.

The difference between theoretical and experimental values.

The pH reaction endpoint is the theoretical equivalence point of the acid-base reaction, and pH is not necessarily equal to 7.

The pH titration endpoint is the point at which the indicator changes color.

The closer these two points are in the trial, the better.

The phenomenon of titration endpoints.

What is the titration endpoint?

Reaction endpoints and titration midpoints.

Titration of the middle power and endpoint of the reaction.

Is the titration endpoint the reaction endpoint?

The titration endpoint is exactly the reaction.

Titrate the endpoint and happen to be a complete reaction.

What is the endpoint error of titration.

Methods for determining the endpoint of titration.

How to answer the phenomenon of the titration endpoint.

What is the endpoint of neutralization titration?

Experimental endpoint phenomena for neutralization titration.

The operation process of redox titration and neutralization titration is to use a potentiometric titrator to determine the endpoint of acid-base titration, what problems should be paid attention to titration analysis. Swipe up.

1. Near the end point: titration to the appearance of transition color.

2. The end point of the dotted key: all the previous colors disappear. If the endpoint cannot be determined, the volume of the standard solution consumed at the time of the suspect endpoint should be recorded first.

Continue the titration to do the following validation. (1) Continue to add 1 2 drops of the standard solution to the sample solution, the color of the solution has not changed significantly, and the suspicious endpoint is the real endpoint, and the original record is effective. (2) Continue to add 1 2 drops of the standard solution to the sample solution, the color of the solution has changed significantly, the suspicious endpoint is not the real endpoint, and the original record is invalid.

Explanation: Abbreviated as end point. In titration analysis, when the titration is reached to the equivalence point, there is often no appearance effect to judge, and the termination of the titration is often determined by the color change of the indicator, and the discoloration point of the indicator is the end point of the titration.

The error caused by the inconsistency between the titration end point and the equivalence point is called the end point error.

In titration analysis, when titrated to the same point, there is often no appearance effect to judge, and the termination of titration is often determined by the color change of the indicator, and the discoloration point of the indicator is the end point of the titration.

The titration endpoint can also be based on the potential and conductivity of the titration system.

and absorbance. This requires the help of instruments.

Indicator is a kind of chemical reagent, under certain medium conditions, its color can change, can produce turbidity or precipitation, and fluorescence, etc., it is commonly used to test the acidity and alkalinity of the solution, titration analysis is used to indicate the titration endpoint, environmental detection of harmful substances.

Indicator selection for the titration endpoint:

Acid-base indicator.

can be neutralized in the reaction.

There is a color change at the endpoint, so the appropriate indicator must be selected for the endpoint.

In order to accurately judge the titration endpoint, it is necessary to select an acid-base indicator with obvious discoloration, the pH of the discoloration range and the pH of the parallel wheel just neutralizing the orange stove.

The narrower the discoloration range of the indicator, the better, and a slight change in pH will change the color of the indicator, litmus.

Due to the wide range of discoloration of the solution and the fact that the color change at the end of the titration is not easy to observe, it is used in neutralization titration.

We do not adopt the credit of the army.

What is the difference between stoichiometric points and titration endpoints in titration analysis

The end point of titration is the discoloration point of the indicator, which varies from indicator to indicator.

The stoichiometric point is the point at which the reaction is completed, and the simplest example is the point at which hydrochloric acid and caustic soda react completely according to the stoichiometric number 1:1.

The stoichiometric point is the theoretical endpoint, and the titration endpoint is the endpoint of the indicator discoloration (in the case of acid-base indicators, when the acid-base concentration ratio of the indicator is 1:1). When the type of reaction has been determined and the indicator has been selected, the difference between the theoretical endpoint and the indicator endpoint is determined, and this difference does not change its value and direction (plus or minus) depending on the number of titrations, the person and the laboratory.

Therefore, it is consistent with the unidirectionality, repeatability and correctability of systematic error. Therefore, the titration endpoint error is a systematic error.

No. The titration endpoint is the point at which the indicator changes color during the titration, and the exact reaction point refers to the point at which the acid reacts with the base, at which time the hydrogen ionization provided by the acid is exactly equal to the hydroxide ion provided by the base.

Just around the time of the reaction point, a drop of acid or base can cause a large change in pH (titration mutation), and the selection indicator can be within this range.

It happens to be neutral, i.e. the pH of the solution is 7, these three points are theoretically different, but for strong acids.

The reaction with a strong base can be considered to be the same point and is within the error range.

No. The titration endpoint is the point at which the color of the indicator changes abruptly, not necessarily at the point where the acid-base is exactly neutralized.

In titration analysis, when the titration reaches the stoichiometric point, there is often no obvious external feature to judge, and the termination of titration is often determined by the color change of the indicator, and the discoloration point of the indicator is the titration endpoint.

(1) It happens to be a complete reaction, that is, the ratio of the amount of the substance of the acid and base is equal to the ratio of the measurement number of the chemical equation, if the strong acid reacts with the strong base, the solution is neutral at this time; If the weak acid reacts with the strong alkali and the strong alkali is alkaline, the strong acid reacts with the weak alkali and the orange deficit. (2) The end point of the dropping round Tan Shending is broken, that is, the point of discoloration of the indicator, phenolphthalein is pH, and methyl orange is, strictly speaking, it is not exactly neutral. (3) It happens to be neutral, that is, the pH of the solution is 7

These three points are theoretically different, but for the reaction of strong acids and strong bases, they can be considered to be the same point and are within the margin of error.

The titration endpoint is the dot leakage of the indicator discoloration during the titration. The exact reaction point refers to the point at which the acid reacts with the base. At this time, the hydrogen ions supplied by the acid extraction are exactly equal to the hydroxide ions provided by the base.

Just around the time of the reaction point, a drop of acid or base can cause a large change in pH (titration mutation).The selection of indicators is within this range.

Understanding and application of titration curve: The acid-base neutralization titration curve is a curve diagram that reflects the neutralization titration process by taking the volume of the injected acid or alkali solution as the abscissa and the pH of the solution after the neutralization reaction as the ordinate.

The curve diagram of the mutual titration of strong acid and strong base, the shape of the first half and the second half of the body does not change much, but the middle abrupt jump is large (that is, the difference of one drop of acid or alkali solution, the pH of the solution changes greatly, and there is a sudden change). To analyze the size and leakage of ion concentration when strong acid and strong base are titrated with each other, as long as the ionization balance of water is concerned, there is no other equilibrium effect.

The curve of strong acid titration of weak alkali or strong alkali titration of weak acid, the sudden jump is small and relatively gentle; The strong acid titration is due to the low starting point of the weak base of Sobi (because the pH of the weak base is relatively small), and the shape of the first half is different; The starting point of the weak acid of the strong base drop is high (due to the relatively large pH of the weak acid), and the shape of the first half is different. To analyze the ion concentration of a strong base titration of a weak acid or a strong acid titration of a weak base, it is necessary to consider not only the hydrolytic equilibrium of the generated salts, but also the ionization equilibrium of excess weak acids or weak bases and the ionization equilibrium of water.

The principle of indicator selection: the selection of indicators should not only consider the obvious and sensitive discoloration, but also select the discoloration range of the indicator to coincide with the pH jump range during the titration, so that the titration end point (that is, the pH when the acid and base are just neutralized) can be accurately indicated.

Titration analysis method: a reagent solution (i.e., standard solution) of known accurate concentration is added dropwise into the solution of the measured substance by the burette until the two are completely reacted according to the metrological relationship represented by a certain chemical equation, and then according to the stoichiometric relationship of the titration reaction, the concentration and volume of the solution are calibrated, and the content of the measured component is calculated, and the method of quantitative analysis is called titration analysis.

Titration: In the case of titration analysis, the solution of the measured substance is placed in a container (usually an Erlenmeyer flask) and then a standard solution is added to the container dropwise by burette under suitable conditions until the two are completely reactive. Such a process is called titration.

Standard solution (titrant): A solution of a reagent of known accurate concentration.

Calibration: The process of preparing a solution that does not meet the conditions of a reference substance is similar to the required concentration, and then using the reaction between the substance and a reference substance or another standard to determine its exact concentration, which is called calibration.

Stoichiometric point: When the injectable standard solution is completely inverse to the substance being measured according to a certain stoichiometric relationship.

So far, the reaction is said to have reached the stoichiometric point.

Titration endpoint: The titration is carried out until the color of the indicator changes abruptly, which is called the titration endpoint.

Titration error: The titration endpoint and the stoichiometric point are often not the same, and the resulting error in the measurement results is called the endpoint error, also known as the titration error.

It is an analytical method in which the known accurate concentration of the standard solution is added dropwise to the solution of the measured substance until the amount of the added solution substance is exactly completely reacted according to the stoichiometric relationship, and then the content of the measured substance is calculated according to the concentration of the added standard solution and the volume consumed. Since this method of measurement is based on measuring the volume of the solution, it is also called volume analysis.

The pH of the titration endpoint does not have to be 7! Its pH should be determined according to the pH of the added reagent, such as methyl red, the color change range is, if the NaOH is titrated with HCl, the titration end point pH is possible, it depends on your grasp of the end point.

To know the titration endpoint, we must first know the acid-base titration"Stoichiometric points"concept.

The stoichiometric point is also when the acid-base reacts completely, and the pH of the solution is 7However, when titrating, we use the naked eye to determine the reaction of the solution by referring to the discoloration of the reagent. In other words, the titration endpoint refers to the endpoint of the complete acid-base reaction that we judge with the naked eye when the reagent changes color.