Question

Column-I (Compounds) Column-II (Statements) (P) Chiral compound (Q) Compound can show geometrical isomensm (R) Asymmetric compound (S) Contains even double bond equivalent

Short answer

Compound P: (P) Chiral compound, (R) Asymmetric compound; Compound Q: (Q) Compound can show geometrical isomerism; Compound R: (R) Asymmetric compound; Compound S: (S) Contains even double bond equivalent.

Step-by-step solution

Understanding the statements

Before we proceed with matching the compounds to the statements, let's briefly discuss what each statement means: (P) Chiral compound: A compound is chiral if it cannot be superimposed on its mirror image. Chiral compounds typically contain an asymmetric carbon atom, which is a carbon atom bonded to four different groups. (Q) Compound can show geometrical isomerism: Geometrical isomerism occurs when a compound has a restricted rotation, usually due to the presence of a double bond or a ring structure. In these compounds, the atoms bonded to the restricted rotation can have different spatial arrangements, and the resulting isomers are called geometrical isomers. (R) Asymmetric compound: An asymmetric compound has an unequal distribution of atoms or groups. These compounds typically have one or more chiral centers but can also include compounds without chiral centers that have an overall asymmetrical arrangement of atoms. (S) Contains even double bond equivalent: The double bond equivalent (DBE) is a measure of the unsaturation level of a compound, which includes the number of double bonds, triple bonds, and/or rings present within the molecule. An even DBE indicates that the compound has an even number of unsaturated connections.

Analyzing the compounds

Now that we understand the different statements let's apply our knowledge to analyze the four compounds and determine their corresponding characteristics: (P) Chiral compound: Compound P has a chiral center. (Q) Compound showing geometrical isomerism: Compound Q has a restricted rotation due to the presence of a double bond or a ring structure. (R) Asymmetric compound: Compound R has an unequal distribution of atoms or groups. (S) Contains even double bond equivalent: Compound S has an even number of unsaturated connections, such as double bonds, triple bonds, and/or rings.

Matching the compounds with the statements

Based on our analysis in Step 2, we will now match each compound with the appropriate statement(s): - Compound P: Chiral compound, Asymmetric compound - Compound Q: Compound can show geometrical isomerism - Compound R: Asymmetric compound - Compound S: Contains even double bond equivalent In conclusion, Compound P matches with statements (P) and (R), Compound Q matches with statement (Q), Compound R matches with statement (R), and Compound S matches with statement (S).

Key concepts

Geometrical Isomerism

Geometrical isomerism is a type of stereoisomerism. It mainly arises from restricted rotation around a bond. Typically, this happens in double-bonded compounds. The double bond creates a lock, preventing the groups attached to a doubly bonded carbon from rotating freely.
Understanding geometrical isomerism involves looking at positional differences in these groups due to the same structural formula but different spatial arrangements. Cis and trans isomers are two common examples. In a cis isomer, similar groups are on the same side of the double bond, while in a trans isomer, they are on opposite sides.
In a compound with a double bond between two carbon atoms, the rotation is hindered. This results in two or more distinct geometrical isomers, depending on how the different groups are arranged spatially.

• Key feature: Restricted rotation.
• Occurs often in: Double bonds, ring structures.
• Common isomers: Cis and trans.

Understanding geometrical isomerism helps predict molecular properties, such as boiling points or chemical reactivity. These properties might differ significantly between isomers.

Double Bond Equivalents

Double bond equivalents (DBE), also called degrees of unsaturation, are a useful calculation in organic chemistry. They help determine the number of rings, double bonds, and triple bonds in a molecule. Calculating DBE gives insights into the structure of the compound.
To calculate the DBE, we start by taking into account all the atoms present in the compound. The formula for DBE is: \[ DBE = C + 1 + rac{N-H-X}{2} \] Where:

• \(C\) is the number of carbon atoms,
• \(N\) is the number of nitrogen atoms,
• \(H\) is the number of hydrogen atoms, and
• \(X\) is the number of halogen atoms (F, Cl, Br, I).

This formula gives a value that indicates how many double bonds, rings, or triple bonds contribute to the compound's unsaturation.
An even number of DBE means the presence of balanced unsaturation like paired bonds, which could imply structural symmetry in complex molecules. It's a handy shortcut for figuring out the potential structure of an unknown compound, critical in fields like combinatorial chemistry and pharmacology.

Asymmetric Compounds

Asymmetric compounds are fascinating and crucial in chemistry due to their unique properties. By definition, an asymmetric compound lacks symmetry in its structure, which often leads to chiral centers in the molecule. A chiral center usually consists of a carbon atom bonded to four different groups. This prevents the compound from being superimposable on its mirror image.
However, not all asymmetric compounds require a chiral center. They can also be asymmetric due to larger structural features, such as an uneven distribution of different groups around the molecule, which affects overall symmetry. This asymmetry in compounds is vital since it significantly influences chemical behavior and reactions.
Other key features to understand about asymmetric compounds include:

• They can affect physical properties like melting points and solubility.
• In asymmetric synthesis, these compounds are substantial in creating desired molecules for medicinal applications.
• They are often involved in biological processes where chirality is crucial, like enzyme reactions.

Asymmetric compounds play a major role in stereochemistry, impacting how a compound functions biologically and chemically.