Question

Choose the correct option(s): (A) All compounds except III has same degree of unsaturation. (B) III has common name aniline. (C) There are only two compounds which contains only $2^{\circ }$ carbon. (D) Among all compounds there are three different functional groups present.

Short answer

The only statement we can confirm to be true is option (B) III has common name aniline. We do not have enough information about the other compounds to evaluate the other statements.

Step-by-step solution

Identify the compounds

First, we need to identify the given compounds either by their structural formula or by their common names. For III, we have Aniline, which has the structural formula: $$C_6{H}_5-N{H}_2$$ Now, let's analyze each statement based on our knowledge about these compounds.

Analyzing (A) All compounds except III has same degree of unsaturation

To answer this statement, we need to calculate the degree of unsaturation for each compound. The degree of unsaturation is calculated by the formula: Degree of unsaturation = $\frac{NumberofHydrogens-2(Carbons+1)}{2}$ Only compound III (Aniline) is given, so we assume that there are other compounds, without knowing which they are we cannot answer this statement.

Analyzing (B) III has common name aniline

This statement is true, as we have already identified that compound III is Aniline.

Analyzing (C) There are only two compounds which contain only $2^{\circ }$ carbon

Without knowing which other compounds are present in this question, we are unable to determine the number of compounds with only $2^{\circ }$ carbon. Hence, we cannot evaluate this statement.

Analyzing (D) Among all compounds there are three different functional groups present

As only compound III is mentioned in the problem, we can only evaluate the functional groups present in Aniline. Aniline has one functional group, which is an amino group (-NH2) attached to a benzene ring. However, we do not have information about the other compounds, so we cannot determine the total number of different functional groups present among all the compounds. Hence, we cannot evaluate this statement. #Outcome# The only statement we can confirm to be true is option B, where Aniline, or compound III, is given. Unfortunately, we do not have enough information about the other compounds to evaluate the other statements.

Key concepts

Degree of Unsaturation

The degree of unsaturation in organic chemistry helps to determine the number of rings and pi bonds in a molecule. Essentially, it tells how many pairs of hydrogens are not present in the compound, implying double bonds or rings. The calculation can be done using the formula:$$\text{Degree of unsaturation}=\frac{\text{Number of Hydrogens}-2(\text{Carbons +1})}{2}$$This formula gives insight into the molecule's structure even if the actual structure isn't apparent. It's important to remember:

• Each double bond contributes one degree of unsaturation.
• Each ring also contributes one degree of unsaturation.
• Triple bonds contribute two degrees of unsaturation.

Understanding this concept is crucial when analyzing molecules like aniline $C_6{H}_5-N{H}_2$, which is often presented in organic chemistry problems.

Functional Groups

Functional groups are specific groups of atoms within molecules that have certain characteristic properties. They are responsible for the main chemical reactions in which the molecule participates. Identifying these groups is crucial to predict how a molecule will react.For instance, aniline, or $C_6{H}_5-N{H}_2$, contains an amino group $-N{H}_2$ attached to a benzene ring. This specific arrangement leads to distinct properties like basicity and aromaticity. Common functional groups include:

• Hydroxyl group $-OH$
• Carboxyl group $-COOH$
• Amines $-N{H}_2$
• Alkenes $C=C$
• Alkynes $C\equiv C$

Recognizing functional groups aids in determining the compound's behavior under different chemical environments.

Secondary Carbon

In organic chemistry, carbons are classified based on the number of other carbon atoms attached to them. A secondary carbon, denoted as $2^{\circ }$ carbon, is bonded to two other carbon atoms. This classification is vital as it can influence the molecule's reactivity, stability, and how they participate in reactions. For instance, secondary carbons often participate in certain types of reactions like S$\mathrm{N}1$ and S$\mathrm{N}2$. Knowing these distinctions is key for predicting reaction mechanisms. When analyzing a molecule, always:

• Identify the carbon type (primary, secondary, tertiary, or quaternary).
• Understand the implications this has on reactivity.
• Consider how the surrounding groups might affect the carbon's behavior.

This understanding helps in interpreting organic structures and anticipating chemical behavior.