Maleic Acid Formula - Structure, Properties, Uses, Sample Questions - GeeksforGeeks (2025)

Malic acid is an organic compound and its molecular formula is C₄H₆O₅. It is naturally found in only one form L-Malic Acid but can be artificially prepared as D-Malic acid. The only difference between both of them is that in L-Malic acid one OH group is present towards the observer and in D-Malic acid, one OH group is present away from the observer. There are many salts and esters of malic acid which are commonly known as Malates. It is a dicarboxylic acid. It is made by almost all living organisms. It is the reason for the sour taste of some fruits. Unripe apples are an important source of Malic acid. It is even found in watermelon, Cherries and many other fruits and vegetables Artificially prepared malic acid is used as a food additive

The structure of Carbon is a nonmetallic, tetravalent element that is of great use to humans. Its name is derived from Latin carbo which means charcoal or ember. Even though carbon is only 0.025% of the earth’s crust and 0.03% in the atmosphere it is of great importance to mankind. Carbon’s abundance and its ability to form polymer at normal is the reason it is commonly found in all living forms.

There are two different structures of Malic Acid. It is naturally found in only one form L-Malic Acid but can be artificially prepared as D-Malic acid. The only difference between both of them is that in L-Malic acid one OH group is present towards the observer and in D-Malic acid, one OH group is present away from the observer. There are two OH functional groups present. The IUPAC name of malic acid is But-2-enedioic acid

Physical and chemical properties of Malic Acid

• It appears as a white crystalline powder.
• The density of malic acid is 1.59 g/cc.
• The molar mass of Malic Acid is 116 g/mol.
• It has a smooth Tart taste.
• It is highly soluble in all polar solvents like methanol, ethanol, and acetone.
• It is generally stable at room temperature and in general storage conditions.
• It is almost odorless.
• When heated above 140° Celsius it decomposes to emit acrid smoke and irritating fumes.
• Malic Acid is a weak diprotic acid.
• The melting point of Malic Acid is 135° C.

Malic acid is used to make Fumaric acid by the process of isomerism malic acid is converted into fumaric acid.

C₄H₄O_{4 (cis)} ————-> C₄H₄O_4(trance)

Uses of Malic Acid

• It is used for the treatment of dry mouth.
• It is sometimes used for the treatment of Fatigue, Fibromyalgia, and some skin conditions.
• It is used in cosmetic products to adjust the pH of makeup products.
• It is used as a flavoring agent due to its tart taste.
• It is used in skincare products for its skin hydrating properties.

Sample Questions

Question 1: What happens when Malic acid is heated?

Answer:

It is generally stable at room temperature and in general storage conditions. When heated above 140 celsius it decomposes to emit acrid smoke and irritating fumes.

Question 2: Is Malic acid strong or weak in nature?

Answer:

It is a diprotic acid like all the other organic acid found in nature it is a weak acid.

Question 3: Is malic acid soluble in water. If not what is it soluble?

Answer:

It is highly soluble in water and It is also highly soluble in all polar solvents like methanol, ethanol, and acetone.

Question 5: What is the IUPAC name of Malic acid?

Answer:

Malic acid is an organic compound and the molecular formula of C₄H₄O₄. It is a dicarboxylic acid. The IUPAC name of malic acid is But-2-enedioic acid

Question 6: Is Malic acid found in nature. If yes what are the good sources of malic acid?

Answer:

It is made by almost all living organisms, it is the reason for the sour taste of some fruits. Unripe apples are an important source of Malic acid. It is even found in watermelon, Cherries, and many other fruits and vegetables .t is naturally found in only one form L-Malic Acid but can be artificially prepared as D-Malic acid.

Question 7: What are the various forms of malic acid and how are they different?

Answer:

It is of two types. It is naturally found in only one form L-Malic Acid but can be artificially prepared as D-Malic acid. The only difference between both of them is that in L-Malic acid one OH group is present towards the observer and in D-Malic acid, one OH group is present away from the observer.

Question 8: Write a short note on the uses of malic acid.

Answer:

It is used for the treatment of dry mouth. It is sometimes used for the treatment of Fatigue, Fibromyalgia, and some skin conditions. It is used in cosmetic products to adjust the pH of makeup products. It is used as a flavoring agent due to its tart taste. It removes dead skin from being applied to the skin.