Grade 11 : Chemistry - Hydrocarbons (Set 1) | Concept of Maths

Explanation:Alkanes are saturated hydrocarbons containing only single covalent bonds between carbon atoms. The general formula for acyclic alkanes is $C_nH_{2n+2}$, where $n$ is the number of carbon atoms.

Explanation:The continuous carbon chain consists of 3 carbon atoms. The prefix for a 3-carbon chain is 'prop-', and since it contains only single bonds, the IUPAC suffix is '-ane'. Hence, the IUPAC name is propane.

Explanation:In methane ($CH_4$), the central carbon forms four single $\sigma$ bonds with four hydrogen atoms and has zero lone pairs. Four bonding domains require $sp^3$ hybridization.

Explanation:Decarboxylation of sodium ethanoate ($CH_3COONa$) using soda lime removes the $CO_2$ group as $Na_2CO_3$, yielding methane ($CH_4$). The reaction is: $CH_3COONa + NaOH \xrightarrow{CaO, \Delta} CH_4 + Na_2CO_3$.

Explanation:With $sp^3$ hybridization and four bonding pairs symmetrically oriented in 3D space, methane forms a regular tetrahedral shape with a bond angle of $109.5^\circ$.

Explanation:Alkenes are unsaturated hydrocarbons containing one carbon-carbon double bond. The presence of a double bond reduces hydrogen count by 2 compared to alkanes, giving the general formula $C_nH_{2n}$.

Explanation:The main chain consists of 3 carbon atoms with a carbon-carbon double bond starting at position 1. Therefore, its IUPAC name is propene (or prop-1-ene).

Explanation:Each double-bonded carbon atom forms three $\sigma$ bonds and one $\pi$ bond. Three $\sigma$ bonding directions require $sp^2$ hybridization with trigonal planar geometry.

Explanation:Markovnikov's rule states that during electrophilic addition to an unsymmetrical alkene, the acidic hydrogen adds to the carbon with more hydrogen atoms, forming the more stable carbocation intermediate.

Explanation:Ozonolysis cleaves the double bond of ethene ($CH_2=CH_2$). Reductive cleavage with $Zn/H_2O$ breaks the ozonide to yield two molecules of methanal (HCHO).

Explanation:Alkynes contain a carbon-carbon triple bond. The general formula for acyclic alkynes with one triple bond is $C_nH_{2n-2}$.

Explanation:Triple-bonded carbon atoms form two $\sigma$ bonds and two $\pi$ bonds. Two $\sigma$ bonding regions require sp hybridization.

Explanation:Due to sp hybridization of both carbon atoms, the bond angle $H-C\equiv C$ is $180^\circ$, giving ethyne a linear molecular geometry.

Explanation:Terminal alkynes like ethyne have sp-hybridized carbons with 50% s-character. High s-character increases electronegativity, making the attached C-H hydrogen acidic enough to react with strong bases.

Explanation:Benzene is a cyclic aromatic hydrocarbon composed of six carbon atoms arranged in a ring, each bonded to one hydrogen atom, giving the formula $C_6H_6$.

Explanation:Benzene has a delocalized $\pi$-electron cloud above and below the ring, attracting electrophiles. Electrophilic substitution preserves aromatic stability, making it the primary characteristic reaction.

Explanation:Benzene has 6 C-C $\sigma$ bonds and 6 C-H $\sigma$ bonds, totaling $12\ \sigma$ bonds. Delocalization of the $p$-orbitals creates $3\ \pi$ bonds (or equivalent $\pi$-cloud).

Explanation:The Wurtz reaction involves reacting two moles of alkyl halide with metallic sodium in dry ether to form an alkane with double the carbon count: $2R-X + 2Na \xrightarrow{\text{dry ether}} R-R + 2NaX$.

Explanation:Ethane ($CH_3-CH_3$) contains a $C-C\ \sigma$ bond allowing free rotation, resulting in infinite spatial arrangements known as conformers (e.g., eclipsed and staggered conformations).

Explanation:Anhydrous $AlCl_3$ acts as a Lewis acid catalyst that accepts a chloride ion from the alkyl halide to generate the electrophilic carbocation ($CH_3^+$) needed for Friedel-Crafts alkylation.