Question

Which acid is not involved in above reactions? (A) Maleic acid (B) Fumaric acid (C) Tartaric acid (D) Malonic acid

Short answer

(C) Tartaric acid

Step-by-step solution

Research the properties of the given acids

Fumaric, Maleic, Tartaric, and Malonic acids are all organic acids with varying properties. Let's list some information about each acid: - Maleic acid (COOH-CH=CH-COOH) is a dicarboxylic acid with an alkene functional group. It forms cyclic anhydrides and participates in various organic reactions like Diels-Alder reactions. - Fumaric acid (COOH-CH=CH-COOH) is a geometric isomer of Maleic acid and is also a dicarboxylic acid with an alkene functional group. It is less soluble in water than Maleic acid. - Tartaric acid (HOOC-CHOH-CHOH-COOH) is a dicarboxylic acid with two hydroxyl groups and is often found in fruits like grapes. It acts as a chiral molecule and has two enantiomers. - Malonic acid (HOOC-CH2-COOH) is also a dicarboxylic acid with no additional functional groups. It is used in the synthesis of various organic compounds like barbiturates.

Compare properties and functional groups

Based on the properties mentioned above, Tartaric acid has a unique characteristic amongst the given acids - having two hydroxyl groups in addition to the two carboxylic acid groups. This property would make it behave differently in reactions compared to the other given acids, which only have carboxylic acid groups.

Provide an educated guess

Given the information we have on the acids, Tartaric acid stands out as having distinct properties that would make it react differently in reactions compared to the other acids. While we cannot be certain without seeing the specific reactions, our educated guess would be that Tartaric acid is not involved in the given reactions. Answer: (C) Tartaric acid

Key concepts

Dicarboxylic acids

Dicarboxylic acids are organic compounds that contain two carboxyl (COOH) functional groups in their molecular structure. These acids play a significant role in organic chemistry because the presence of two carboxyl groups can influence the compound's reactivity and solubility. Some well-known dicarboxylic acids include maleic acid, fumaric acid, tartaric acid, and malonic acid.

Here are some interesting aspects about dicarboxylic acids:

• They are involved in essential biochemical pathways and industrial applications. For example, fumaric acid is part of the citric acid cycle, which is vital for cellular respiration.
• They have varying degrees of water solubility depending on their molecular structure. Maleic acid, for instance, is more soluble in water than fumaric acid because of its cis configuration, which makes the molecule more polar.
• Dicarboxylic acids can form cyclic anhydrides if they contain an alkene group, as seen in maleic acid, which can participate in Diels-Alder reactions.

Understanding the properties of dicarboxylic acids is crucial when studying organic reactions, as they can exhibit diverse chemical behaviors depending on their structural composition.

Geometric isomers

Geometric isomers, also known as cis-trans isomers, are a type of stereoisomers in which molecules have the same structural formula but differ in the spatial arrangement of groups around a double bond or a ring structure. The most common example of geometric isomers we come across is the difference between maleic acid and fumaric acid.

Here are some important considerations regarding geometric isomers:

• Cis isomers have similar groups on the same side of a double bond, leading to higher polarity, while trans isomers have groups on opposite sides, making them less polar. For instance, maleic acid (cis) is more soluble in water than fumaric acid (trans).
• The physical and chemical properties of geometric isomers can vary significantly due to differences in polarity and molecular shape. This alters their boiling points, melting points, and solubility.
• In organic synthesis, the presence of geometric isomers can greatly affect reaction pathways or the effectiveness of a reaction, such as the formation of cyclic anhydrides from maleic acid.

Understanding geometric isomers is essential in predicting how different molecules will interact in chemical reactions, which is valuable for both academic studies and practical applications in fields like pharmaceuticals.

Chiral molecules

Chiral molecules are fascinating entities in organic chemistry, characterized by their ability to exist in two non-superimposable mirror images known as enantiomers. A classic example is tartaric acid, which has two asymmetric carbon atoms, making it chiral.

Here's what you should know about chiral molecules:

• They are significant in the field of stereochemistry because enantiomers can have vastly different effects in biological contexts, despite having the same molecular formula. This is crucial in the pharmaceutical industry, where one enantiomer of a drug might be therapeutic while the other could be harmful.
• The chirality of a molecule directly affects how it interacts with polarized light. Chiral molecules can rotate the plane of polarized light, known as optical activity, which is used to identify and quantify enantiomers.
• In nature, many biomolecules are chiral, including carbohydrates, proteins, and nucleic acids. Chirality is a fundamental aspect of molecular interactions, impacting everything from enzyme activity to the formation of double helixes in DNA.

Understanding chirality is vital for grasping the complexities of molecular interactions and their implications in synthetic and natural settings.