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Citric acid is a tribasic weak acid that comes in two varieties: monohydrate and water-free (anhydrous). Citrus fruits, such as lemons and oranges, contain this acid. It has a sour taste without any odor. Citric acid is a white crystalline substance that is monoclinic. As a result of being a Tribasic acid, to make acidic salts of Citric acid, one has to do it by carefully regulating pH levels before the complex crystallizes. Sodium citrate is an example of an acidic salt produced from this acid.
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Key Terms: Citric Acid, Acid, Properties of Citric Acid, Uses of Citric Acid, Citric Acid Preparation
What is Citric Acid?
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Citric acid can be explained as a tribasic weak acid that is sour in taste and does not have any odor. Carl Wilhelm Scheele, a scientist, was the first to isolate this organic acid in the year 1784. Because it resembles table salt, it is referred to as sour salt in the marketplace.
C6H8O7 is the chemical formula for citric acid. Citric acid crystals have a white color in their natural state, which you can see on the tops of sour candies.
Chemical Structure of Citric Acid
Preparation of Citric Acid
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The process of preparing Citric Acid can be explained in five basic steps-
Step 1: To get a good amount of crystallized Citric acid, you'll need 450 mL lemon juice. A pH strip may be used to test the lemon juice. The pH level should be approximately 2 or 3 on a scale of 1 to 10.
Step 2: Toss in a few drops of eye drops containing 10% strength sodium hydroxide and retest the solution. Using the coffee filter, pour the solution into a second glass. Check for any solid particles in the solution you put into a new flask at this point.
Step 3: Mix 28 grams of calcium chloride with 70 mL of distilled water in a single glass and boil.
Step 4: Using a coffee filter, filter the solution one more to remove the calcium citrate. As the calcium citrate is being removed, combine it with significantly diluted sulfuric acid and stir well. Filter the solution and store the citric acid in a beaker with water.
Step 5: Heat the solution over medium heat until the water in the beaker has evaporated. Finally, strain out the citric acid and set it aside to cool.
Properties of Citric Acid
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The characteristics of citric acid are-
- Citrate is the colloquial term for citric acid, and its scientific IUPAC name is 2-Hydroxypropane-1,2,3-tricarboxylic acid.
- The density of citric acid is 1.66 g/cm3. One of the most essential qualities of every chemical molecule is its density, which determines how much of it can mix with any given material.
- Citric acid has a molecular weight of 210.14 g/mol when it is present in monohydrate form.
Uses of Citric Acid
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Citric acid is beneficial to humans in a variety of ways. Some of the most common applications are listed below.
- Citric acid, for starters, adds tartness to beverages and enhances the flavors of fruits and berries.
- It also boosts antimicrobial preservatives and allows for pH changes, resulting in consistent acidity in soft drinks.
- Citric acid lowers the pH of frozen fruits, making oxidative enzymes inactive.
- This acid is used in medicines as an effervescent in combination with bicarbonates to speed up the dissolving of active substances.
Citric Acid Cycle Reactions
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Citric acid is the result of the condensation of Oxaloacetic acid and Acetyl CoA. At the ketone carbon, the acetyl group CH3COO from CoA is transferred to oxaloacetic acid. The net consequence is that a four-carbon piece and a two-carbon piece join together to produce acid, which has six carbons. This is known as acid synthesis.
- To isomerize the location of the -OH group on citric acid, there are two stages.
- Alcohol is dehydrated in order to create alkene. The cis-aconitic acid retains its grip on the enzyme aconitase in the next stages.
- Hydration does not obey Markovnikov's rule. Furthermore, the reaction has the net effect of moving the – OH group from C-3 to C-2, resulting in isocitric acid.
- The oxidation process happens when alcohol is converted to a ketone.
- It creates Malic acid by placing the – 0H group, which must be next to a carboxylic acid group.
- The last step in the citric acid cycle is the oxidation of alcohol to a key tone, which produces oxaloacetic acid.
Citric Acid Cycle Reactions
Things to remember
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- Citric acid is a tribasic and weak acid that can be found in fruits like- lemons, oranges.
- The chemical formula of this acid is- C6H8O7
- It i8s also called sour salt at the market.
- It boosts the antimicrobial preservatives and allows for pH changes, which creates consistent acidity in soft drinks.
- Citric acid can be made from lemon juices in five easy steps.
Solved questions
Q1: What are the dangers of citric acid? (4 Marks)
Ans. Companies manufacture citric acid via chemical processes, according to the Food and Drug Administration (FDA). There is now no evidence that artificially ingesting citric acid is harmful to one's health or physique (when consumed in large amounts for extended periods). There have been many reports of people being ill as a result of the addition, as well as allergic responses. Some patients have reported joint discomfort, edema, and stiffness, as well as muscle and gastrointestinal problems. Shortness of breath was also a problem for some folks. Consuming citric acid from fruits and vegetables such as lemons and limes, on the other hand, poses no risk.
Q2. Is it true that citric acid is a disinfectant? (2 Marks)
Ans: Because it destroys germs, mold, and mildew, it is useful for general disinfection and cleaning. Lime, rust, calcium deposits, soap scum, and hard water stains may all be removed. Many cleaning products use it as a preservative.
Q3. What is the difference between citric acid and ascorbic acid? (2 Marks)
Ans. Ascorbic acid and citric acid are two different kinds of acids used for food preservation. They are not identical, and ascorbic acid has higher acidity than vitamin C. Their chemical structures differ somewhat in terms of science, resulting in varied functioning.
Q4. Which microorganism is helpful in the synthesis of citric acid? (2 Marks)
Ans: The fungus Aspergillus niger may be used to make citric acid. It's also used in the manufacture of gluconic acid, which is an organic acid. It causes black mold illness, as well as some plants and fruits, under specific conditions.
Q.5. What are the applications of citric acid? (3 Marks)
Ans. Citrus fruits contain citric acid, which is an organic chemical. It's a natural preservative that's also used to impart an acidic (or sour) flavor to foods and soft beverages. It's an important biochemical step in the citric acid cycle, and it's found in nearly every living organism's metabolism.
Q.6. Is citric acid a poison? (3 Marks)
Ans. Citric acid is found naturally in citrus fruits, but synthetic versions (usually produced from a mold type) are widely used in meals, medicines, vitamins, and cleaning products. While mold remnants from the production process might cause allergies in certain people, citric acid is generally thought to be a harmless ingredient.
Q.7. Where in nature can you find citric acid? (4 Marks)
Ans: Citric acid is a natural preservative utilized in the food business to give meals and soft drinks a sour flavor. Citric acid, on the other hand, is added chemically and is not found naturally in any of these foods.
Citric acid may be found naturally in fruits and vegetables such as lemons, limes, oranges, grapefruits, pomelos, and tangerines. Citric acid, on the other hand, is found in small amounts in nearly all fruits. Pineapple, strawberries, cherries, and tomatoes are among these fruits. Consumption of these fruits promotes healthy metabolism and prevents bloating and constipation.
Q.8 How do you make a citric acid solution? (2 Marks)
Ans. To make the citric acid solution, combine citric acid crystals (also known as sour salt) with 1 or 2 quarts of distilled boiling water for every pound of citric acid. Place the citric acid crystals in a non-metal dish and slowly pour in the boiling water, stirring constantly with a non-metal spoon.
Also Read :
| Related Articles | ||
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| Acid, Bases and Salts | Acid Vs Bases | Ammonium Chloride |
| Acid Strengths | Salt Analysis | pH for Weak Acids |
| Tartaric Acid | Dilution Formula | Strong Acids |
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