Why do we use different types of indicator in acid-base titration?
Because a noticeable pH change occurs near the equivalence point of acid-base titrations, an indicator can be used to signal the end of a titration. When selecting an indicator for acid-base titrations, choose an indicator whose pH range falls within the pH change of the reaction.
Why do you need to use two indicators here?
To neutralize a strong acid with a weak base gives an acid salt and thus a pH on the acid side. Conversely a weak acid with a strong base gives an alkaline salt, so a pH on the alkaline side. Thus you may be instructed to use different indicators to give a colour change at the right point.
Which titration is used for two types of indicators?
Acid–base titration
| Indicator | Color on acidic side | Range of color change (pH) |
|---|---|---|
| Methyl red | Red | 4.4–6.3 |
| Litmus | Red | 5.0–8.0 |
| Bromothymol blue | Yellow | 6.0–7.6 |
| Phenolphthalein | Colorless | 8.3–10.0 |
Why are different types of indicator required for different pH?
Acid and base indicators are used in chemistry to determine a substance’s pH. They change to different colors depending on whether they are added to an acid, a base or a neutral substance. Most indicators are themselves weak acids and respond to changes in the hydrogen ion concentration.
Why is universal indicator not used in titration?
The universal indicator is not used in titration because they have different pH ranges. It becomes difficult to determine the exact pH of the solution. Therefore, universal indicator is not used in titration.
What is the purpose of using an indicator for a titration?
In a titration, you determine an unknown concentration of a sample by adding a second reactant of known concentration. In many titrations, you use a chemical called an indicator, which lets you know when the titration finishes.
What is titration and what are different types of titration?
Such titrations, classified according to the nature of the chemical reaction occurring between the sample and titrant, include: acid-base titrations, precipitation titrations, complex-formation titrations, and oxidation-reduction (redox) titrations.
What are two other commonly used acid base indicators and their colors for both acid and base ranges?
Table of Common pH Indicators
| Indicator | Acid Color | Base Color |
|---|---|---|
| methyl orange | red | yellow |
| bromocresol green | yellow | blue |
| methyl red | yellow | red |
| bromothymol blue | yellow | blue |
Why do we use indicators in chemistry?
The common application of indicators is the detection of end points of titrations. The colour of an indicator alters when the acidity or the oxidizing strength of the solution, or the concentration of a certain chemical species, reaches a critical range of values.
Which indicator is best used in a titration?
Choosing indicator for titrations Strong Acid v Strong Base. The diagram shows the pH curve between strong acid to a strong base, for methyl orange and phenolphthalein. Strong Acid v weak base. In this graph the indicator methyl orange is used and change color of end product from yellow to orange which is very close to equivalence Weak Acid v strong base. Weak acid v weak base.
What makes a good indicator for titration?
In all cases, though, a good indicator must have the following properties: The color change must be easily detected. The color change must be rapid. The indicator molecule must not react with the substance being titrated. To minimize errors, the indicator should have a pKin that is within one pH unit of the expected pH at the equivalence point of the titration.
Which acid base indicator should be used?
Natural Dyes. This important acid-base indicator is produced from lichens. Lichens are differentiated into forms that grow on plants,and those that grow on soil and rocks.
What are different types of indicator used in titration?
Titration Indicator Titration. It is also known as titrimetry and volumetric analysis [1]. Indicator. A substance that changes color of the solution in response to a chemical change. Titration Procedure. Types of Titration. Indicators. The pH range of indicator. The pH range of indicators. Choosing indicator for titrations.