Indicators are substances that change color in response to changes in pH. They help determine the acidity, basicity, or neutrality of a solution. Universal indicators and litmus papers are two types of indicators that are widely used in chemistry.
What is the difference between litmus paper and universal indicator? Litmus paper turns red in acidic solutions and blue in alkaline solutions, whereas the universal indicator shows a wide range of colors, giving a more accurate measure of acidity or alkalinity.
Key Areas Covered
1. What is a Litmus Paper
– Definition, Features
2. What is a Universal Indicator
– Definition, Features
3. Similarities Between Litmus Paper and Universal Indicator
– Outline of Common Features
4. Difference Between Litmus Paper and Universal Indicator
– Comparison of Key Differences
5. FAQ: Litmus Paper and Universal Indicator
– Answers to Frequently Asked Questions
Key Terms
Litmus Paper, pH, Universal Indicator
What is a Litmus Paper
Litmus paper is a piece of paper treated with natural dye which is extracted from lichens. This dye is made up of different components mixed in it. It can change color depending on acidity or alkalinity.
There are two types of litmus papers in the market. They are red litmus and blue litmus papers. Blue litmus paper will turn red if immersed in an acidic solution. In contrast, red litmus paper will turn blue when immersed in a basic solution. This color change helps one to quickly determine whether a substance is alkaline, neutral, or acidic in nature. Moreover, red litmus paper remains red in acidic or neutral solutions, and blue litmus paper remains blue in basic and neutral solutions.
This product might look so simple; however, it’s frequently found in various laboratories, including classrooms. Though litmus paper can be used to identify whether a solution is acidic or basic, it has its own drawbacks. A litmus paper does not have the ability to accurately determine the exact pH value of a solution.
What is a Universal Indicator
A universal indicator is a unique mixture of various chemicals. This helps scientists to determine the pH of a solution. When the solution is very acidic, the indicator changes to a bright red. As the acidity drops, the color changes from orange to yellow and eventually to green for neutral solutions. As the solution becomes more alkaline, the colors change to blue, indigo, and finally, a deep violet for highly alkaline substances. This happens because the indicator’s chemicals interact with hydrogen ions (H+), causing different colors depending on how many hydrogen ions are in the solution.
Universal indicators exist either as liquids or paper strips. When more exact measurements are taken, liquid form is usually used inside test tubes, while paper strips are good for fast approximate estimation purposes.
The main use of universal indicators is the measurement of the pH of a solution. Universal indicators can be used to determine the end point of acid base titrations. However, they are not as accurate as pH meters. Universal indicators can also be used to assess the pH of water bodies in the process of testing water quality. Moreover, they are used in general experiments involving acid base reactions to determine the pH.
Similarities Between Litmus Paper and Universal Indicator
- Litmus paper and universal indicator are pH indicators.
- Both detect acidity and alkalinity.
- Both undergo a color change in response to the pH of a solution.
Difference Between Litmus Paper and Universal Indicator
Definition
- Litmus paper is a simple test strip that changes color to indicate whether a solution is acidic (red) or alkaline (blue). Universal indicator, on the other hand, is a pH test solution or paper that shows a wide range of colors to indicate the exact pH level of a solution, from acidic to alkaline.
Colors
- Red litmus turns blue in basic solutions, while blue litmus turns red in acidic solutions, whereas a universal indicator shows a wide range of colors across the pH scale.
Precision
- Litmus papers can only differentiate between acidic and alkaline solutions, while universal indicators can determine the approximate pH value of a solution in a range of 1-14.
Production
- Litmus paper is made from a natural dye extracted from lichens, while universal indicator is a mixture of several synthetic dyes.
Conclusion
Litmus paper and universal indicator are both indicators widely used in acid base reactions to determine the acidity or basicity of the solutions. They give different colors based on the acidity, basicity, or neutrality of a solution. Litmus paper is a simple test strip that changes color to indicate whether a solution is acidic (red) or alkaline (blue). Universal indicator, on the other hand, is a pH test solution or paper that shows a wide range of colors to indicate the exact pH level of a solution, from acidic to alkaline. This is the main difference between litmus paper and universal indicator.
FAQ: Litmus Paper and Universal Indicator
1. What is the difference between a universal indicator and a pH paper?
A universal indicator is a solution that changes color to show how acidic or alkaline a solution is, covering a wide pH range. pH paper is similar but comes as a strip and gives faster, though less accurate, results.
2. How is litmus paper used as an indicator?
Litmus paper is dipped in the solution. If the blue litmus paper turns red, the solution becomes acidic. If the red litmus paper turns blue, then the solution is basic.
3. What is litmus paper made up of?
Litmus paper is made from wood cellulose paper that’s treated with litmus, a dye taken from lichens and soaked in either an acidic or alkaline solution to create red or blue litmus paper.
4. Why does litmus paper change color?
Litmus paper contains a dye extracted from lichens. This dye changes color based on the pH of the solution. In acidic solutions, the dye reacts to turn red. In basic solutions, it turns blue. This color change indicates whether a substance is acidic or basic.
5. What are the benefits of litmus paper?
Litmus paper is quick, simple, and portable. It shows if something is acidic or basic fast. It is useful for both laboratory and everyday applications. It’s also inexpensive and easy to use.
Reference:
1. “Universal Indicator.” Wikipedia. Wikipedia Foundation.
2. “Litmus Paper – Everything you need to know.” Science Equip.
Image Courtesy:
1. “Red and blue litmus papers” By Kanesskong – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Skala boja 2” By Dejan Jovic DJ – Own work (CC BY-SA 4.0) via Commons Wikimedia
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