Table of Contents
- 1 What are the characteristics of a good acid-base indicator?
- 2 What are the characteristics of a substance which makes it a good pH indicator?
- 3 Which of these is not a characteristic of a good indicator for the titration of a weak acid with a strong base?
- 4 What is a suitable indicator?
- 5 How can you tell if titration is successful?
- 6 What is the suitable indicator for strong acid and weak base?
- 7 Which indicator is best used in a titration?
- 8 Which acid base indicator should be used?
What are the characteristics of a good acid-base indicator?
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.
What makes a good indicator for titration?
A strong acid- strong base titration is performed using a phenolphthalein indicator. Phenolphtalein is chosen because it changes color in a pH range between 8.3 – 10.
What are the characteristics of a substance which makes it a good pH indicator?
pH indicators are weak acids that exist as natural dyes and indicate the concentration of H+ (H3O+) ions in a solution via color change. A pH value is determined from the negative logarithm of this concentration and is used to indicate the acidic, basic, or neutral character of the substance you are testing.
What are the three requirements for a successful acid-base titration?
Titrations reactions mixture must be (i) rapid; (ii) quantifiable by means of an easily observed end-point; (iii) have known and definite stoichiometry.
Which of these is not a characteristic of a good indicator for the titration of a weak acid with a strong base?
Weak Acid and Strong Base Titration Problems
| HF | F- | |
|---|---|---|
| Initial | 7.5 mmol | 0 mmol |
| Add | 0 mmol | |
| Change | -3 mmol | 3 mmol |
| Equilibrium | 4.5 mmol | 3 mmol |
Is best indicator used in titration of weak acid and strong base?
Choice of Indicators
| Types of titration | Indicators |
|---|---|
| Strong acid-strong base | Phenolphthalein is usually preferred because of its more easily seen colour change. |
| Weak acid-strong base | Phenolphthalein is used and change sharply at the equivalence point and would be a good choice. |
What is a suitable indicator?
The suitable indicators for the following titrations are, (i) Strong acid Vs strong base: Phenolphthalein (pH range 8.3 to 10.5), methyl red (pH range 4.4 – 6.5) and methyl orange (pH range 3.2 to 4.5). (ii) Weak acid Vs strong base: Phenolphthalein. (iii) Strong acid Vs weak base: Methyl red and methyl orange.
What do you know about indicators?
Indicators are substances that change colour when they are added to acidic or alkaline solutions. Litmus, phenolphthalein, and methyl orange are all indicators that are commonly used in the laboratory.
How can you tell if titration is successful?
Watch the solution closely for the color change. Once the solution begins to change color and the new color persists for at least 30 seconds, you have reached the end point of your titration.
Which indicator is suitable for a weak acid-strong base titration and why?
Choosing an appropriate indicator for a titration
| pH | 0 | Use |
|---|---|---|
| methyl orange | < 3.1 | strong acid + weak base |
| bromocresol green | < 3.8 | strong acid + weak base |
| methyl red | < 4.4 | strong acid + weak base |
| litmus | < 5.0 |
What is the suitable indicator for strong acid and weak base?
Phenolphthalein
In the titration of strong acid and weak base, the indicator used is Methyl Orange. Note: Phenolphthalein is used as an indicator for Strong acid -strong base titration.
What is a strong acid and a strong base?
Acids and bases that are completely ionized when dissolved in water are called strong acids and strong bases There are only a few strong acids and bases, and everyone should know their names and properties. These acids are often used in industry and everyday life.
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 are the indicators used in titrations?
Indicators are substances that change colour when they are added to acidic or alkaline solutions
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.