Complete Guide To Phenolphthalein Indicator Colors In Acidic Environments

Feed 16 Jun 2024

Which of the following pH range and color is correct with respect to phenolphthalein indicator in acidic medium?

Phenolphthalein is a chemical compound that is used as an indicator in acid-base titrations. It is colorless in acidic solutions and turns pink in basic solutions. The pH range of phenolphthalein is from 8.2 to 10.0. In acidic solutions, the phenolphthalein molecule is protonated, which means that it has a positive charge. This protonated form of phenolphthalein is colorless. In basic solutions, the phenolphthalein molecule is deprotonated, which means that it has a negative charge. This deprotonated form of phenolphthalein is pink.

The correct answer to the question is colorless.

Phenolphthalein is an important indicator because it is very sensitive to changes in pH. This makes it useful for titrating weak acids and bases.

Phenolphthalein was first synthesized in 1871 by Adolf von Baeyer. It is still one of the most commonly used indicators in acid-base titrations today.

Which of the following pH range and colour is correct with respect to phenolphthalein indicator in acidic medium?

Color: Colorless in acidic solutions, pink in basic solutions.
pH range: 8.2 to 10.0
Chemical formula: C20H14O4
Molecular weight: 318.33 g/mol
CAS number: 77-09-8

Phenolphthalein is an important indicator because it is very sensitive to changes in pH. This makes it useful for titrating weak acids and bases.

Color

The color of phenolphthalein is directly related to the pH of the solution it is in. In acidic solutions, the phenolphthalein molecule is protonated, which means that it has a positive charge. This protonated form of phenolphthalein is colorless. In basic solutions, the phenolphthalein molecule is deprotonated, which means that it has a negative charge. This deprotonated form of phenolphthalein is pink.

The pH range of phenolphthalein is from 8.2 to 10.0. This means that phenolphthalein will be colorless in solutions with a pH below 8.2 and pink in solutions with a pH above 8.2.

Phenolphthalein is an important indicator because it is very sensitive to changes in pH. This makes it useful for titrating weak acids and bases.

For example, phenolphthalein can be used to titrate a solution of hydrochloric acid with a solution of sodium hydroxide. The phenolphthalein will be colorless at the start of the titration, but it will turn pink when the equivalence point is reached. This will indicate that all of the hydrochloric acid has been neutralized by the sodium hydroxide.

Phenolphthalein is a versatile indicator that can be used in a variety of applications.

pH range

The pH range of phenolphthalein is from 8.2 to 10.0. This means that phenolphthalein will be colorless in solutions with a pH below 8.2 and pink in solutions with a pH above 8.2.

Colorless in acidic solutions: In acidic solutions, the phenolphthalein molecule is protonated, which means that it has a positive charge. This protonated form of phenolphthalein is colorless.
Pink in basic solutions: In basic solutions, the phenolphthalein molecule is deprotonated, which means that it has a negative charge. This deprotonated form of phenolphthalein is pink.

The pH range of phenolphthalein is important because it determines the color of the indicator in different solutions. This makes phenolphthalein a useful indicator for acid-base titrations.

Chemical formula

The chemical formula of phenolphthalein is C20H14O4. This formula tells us that phenolphthalein is composed of 20 carbon atoms, 14 hydrogen atoms, and 4 oxygen atoms.

The chemical formula of phenolphthalein is important because it helps us to understand the structure and properties of the molecule. For example, we know that phenolphthalein is a weak acid because it has a carboxylic acid group (-COOH) in its structure. We also know that phenolphthalein is a colorless compound in its acidic form and a pink compound in its basic form because of the presence of a phenolphthalein group (-C6H4OH) in its structure.

The chemical formula of phenolphthalein is also important for its use as an indicator in acid-base titrations. Phenolphthalein is a very sensitive indicator, which means that it can detect even small changes in pH. This makes it a useful indicator for titrating weak acids and bases.

Overall, the chemical formula of phenolphthalein is an important piece of information that helps us to understand the structure, properties, and uses of this compound.

Molecular weight

The molecular weight of phenolphthalein is 318.33 g/mol. This means that one mole of phenolphthalein weighs 318.33 grams.

The molecular weight of phenolphthalein is important because it helps us to understand the properties of the compound. For example, the molecular weight of phenolphthalein tells us that it is a relatively large molecule. This is important because it affects the solubility and other properties of phenolphthalein.

The molecular weight of phenolphthalein is also important for its use as an indicator in acid-base titrations. The molecular weight of phenolphthalein tells us how much of the compound is needed to make a given volume of solution. This is important because it allows us to accurately determine the concentration of an acid or base.

Overall, the molecular weight of phenolphthalein is an important piece of information that helps us to understand the properties and uses of this compound.

CAS number

The CAS number is a unique identifier that is assigned to each chemical substance. The CAS number for phenolphthalein is 77-09-8.

The CAS number is important because it allows us to track and identify chemical substances. This is important for a variety of reasons, including safety, regulation, and research.

For example, the CAS number can be used to:

Identify the chemical substance in a product
Look up information about the chemical substance, such as its properties and hazards
Track the movement of the chemical substance in commerce
Regulate the use of the chemical substance

The CAS number is a valuable tool that can be used to ensure the safe and responsible use of chemical substances.

In the case of phenolphthalein, the CAS number can be used to identify the compound and look up information about its properties and hazards. This information can be used to ensure the safe use of phenolphthalein in a variety of applications, including as an indicator in acid-base titrations.

FAQs on Phenolphthalein Indicator in Acidic Medium

Phenolphthalein indicator is a chemical compound that is used to indicate the presence of an acid or a base in a solution. It is colorless in acidic solutions and turns pink in basic solutions. The pH range of phenolphthalein is from 8.2 to 10.0.

Here are some frequently asked questions about phenolphthalein indicator in acidic medium:

Question 1: What is the color of phenolphthalein indicator in acidic medium?

Answer: Phenolphthalein indicator is colorless in acidic medium.

Question 2: What is the pH range of phenolphthalein indicator?

Answer: The pH range of phenolphthalein indicator is from 8.2 to 10.0.

Question 3: What is the chemical formula of phenolphthalein indicator?

Answer: The chemical formula of phenolphthalein indicator is C20H14O4.

Question 4: What is the molecular weight of phenolphthalein indicator?

Answer: The molecular weight of phenolphthalein indicator is 318.33 g/mol.

Question 5: What is the CAS number of phenolphthalein indicator?

Answer: The CAS number of phenolphthalein indicator is 77-09-8.

Question 6: What are the applications of phenolphthalein indicator?

Answer: Phenolphthalein indicator is used in a variety of applications, including acid-base titrations, pH measurements, and as a laxative.

These are just a few of the frequently asked questions about phenolphthalein indicator in acidic medium. If you have any other questions, please feel free to contact us.

We hope this information has been helpful. Thank you for reading!

Transition to the next article section:

In the next section, we will discuss the applications of phenolphthalein indicator in more detail.

Conclusion

In this article, we have explored the topic of "which of the following pH range and colour is correct with respect to phenolphthalein indicator in acidic medium". We have learned that phenolphthalein is a chemical compound that is used as an indicator in acid-base titrations. It is colorless in acidic solutions and turns pink in basic solutions. The pH range of phenolphthalein is from 8.2 to 10.0.

We have also discussed the chemical formula, molecular weight, and CAS number of phenolphthalein. We have also explored the applications of phenolphthalein indicator in more detail.

We hope that this article has been helpful in providing you with a better understanding of phenolphthalein indicator. If you have any other questions, please feel free to contact us.

Thank you for reading!

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