Test: Organic Chemistry - Hydrocarbons - Class 10 MCQ

Catenation refers to the ability of an element, particularly carbon, to form long chains of atoms by bonding with itself. This property is significant in organic chemistry and allows for the formation of various structures such as straight chains, branched chains, and rings.

The Wurtz reaction involves the coupling of alkyl halides using sodium metal to form higher alkanes. For example, when iodomethane (CH₃I) is reacted with sodium, it can produce ethane (C₂H₆).

A homologous series consists of compounds that have the same functional group and similar chemical properties, allowing for systematic study. For example, alkanes, alkenes, and alkynes show similar reactivity patterns within their respective series.

Functional isomerism occurs when compounds have the same molecular formula but differ in their functional groups, leading to different chemical properties. An example includes ethanol (C₂H₅OH) and dimethyl ether (CH₃OCH₃).

2-Methylpropane is a structural isomer of butane. Both have the same molecular formula (C₄H₁₀) but differ in the arrangement of carbon atoms, resulting in different structural forms.

When ethanol undergoes oxidation, it is converted into acetic acid (CH₃COOH). This reaction is significant in organic chemistry and is often catalyzed by agents like potassium dichromate.

Chain isomerism occurs when compounds have the same molecular formula but differ in the arrangement of the carbon skeleton, either as straight or branched chains. This leads to different structural forms with distinct properties.

Alkanes typically undergo substitution reactions, particularly with halogens, where one of the hydrogen atoms is replaced by a halogen atom. For example, methane reacts with chlorine to form chloromethane.

Hydrogenation is an addition reaction where hydrogen is added to an alkene, converting it into an alkane. For instance, ethene (C₂H₄) can be hydrogenated to form ethane (C₂H₆).

Alkynes are classified as unsaturated hydrocarbons because they contain at least one carbon-carbon triple bond. This structural feature makes them more reactive than alkenes and alkanes.

The carbon-carbon double bond in alkenes restricts rotation due to its planar structure, which can lead to the formation of geometric isomers (cis and trans configurations). This characteristic is important in determining the chemical behavior and properties of alkenes.

Position isomerism occurs when compounds have the same molecular formula but differ in the position of a substituent or functional group. For example, pentane (C₅H₁₂) and 2-methylbutane are isomers that differ in the positioning of the methyl group.

The IUPAC suffix "-ene" indicates the presence of a carbon-carbon double bond in alkenes. For example, ethylene (C₂H₄) is an alkene with a double bond between its two carbon atoms.

The -COOH group is the functional group present in carboxylic acids, which gives them acidic properties. For instance, acetic acid (CH₃COOH) is a common carboxylic acid.

During the complete combustion of methane (CH₄) in the presence of sufficient oxygen, the primary products formed are carbon dioxide (CO₂) and water (H₂O). The reaction can be represented as CH₄ + 2O₂ → CO₂ + 2H₂O.

C₂H₅OH (ethanol) is classified as an alcohol due to the presence of the hydroxyl group (-OH) that replaces one or more hydrogen atoms of an alkane. This functional group is what characterizes alcohols.

Alkanes are saturated hydrocarbons where every carbon atom is bonded to the maximum number of hydrogen atoms. This is represented by the general formula C_nH_2n+2, where "n" represents the number of carbon atoms. For example, if n = 3 (propane), the formula is C₃H₈.

Alkynes follow the general formula C_nH_2n-2, where "n" is the number of carbon atoms. This formula indicates the presence of a carbon-carbon triple bond, which reduces the number of hydrogen atoms compared to alkenes and alkanes.

Saturated hydrocarbons, such as alkanes, contain only single bonds between carbon atoms, meaning all available valencies of carbon are satisfied with hydrogen atoms. This structure results in lower reactivity compared to unsaturated hydrocarbons.

The functional group in an organic compound is crucial as it largely determines the chemical reactivity and properties of the compound. For example, the hydroxyl (-OH) group in alcohols imparts specific characteristics that define their behavior in chemical reactions.