Carbon and its Compounds
Frequently Asked Questions
Carbon is a non-metal with atomic number 6, known for forming a huge variety of compounds due to its tetravalency and catenation ability.
The ability of carbon to form four covalent bonds because it has four electrons in its outermost shell (configuration: 2,4).
Catenation is the property of carbon to form long chains and rings by bonding with other carbon atoms.
Carbon achieves a stable configuration by sharing electrons instead of losing/gaining four electrons, thus forming covalent bonds.
A covalent bond is a bond formed when two atoms share electron pairs.
Compounds containing hydrogen and carbon only, such as methane, ethane, ethene, and ethyne.
Hydrocarbons with single covalent bonds (alkanes), general formula: \(C_nH_{2n+2}\).
Hydrocarbons with double or triple bonds (alkenes & alkynes), formulas: alkenes \(\Rightarrow C_nH_{2n}, alkynes \(Rightarrow C_nH_{2n-2}.
\(C_nH_{2n+2} (e.g., methane \(\ce{CH4}\), ethane \(\ce{C2H6}\)).
\(C_nH_{2n}\) (e.g., ethene \(\ce{C2H4\)).
\(C_nH_{2n-2} (e.g., ethyne \(\ce{C2H2\)).
Atoms or groups that determine the characteristic properties of organic compounds, e.g., –OH (alcohol), –COOH (acid).
Alcohol (–OH), Aldehyde (–CHO), Carboxylic acid (–COOH), Ketone (>C=O), Halogens (–X).
A series of compounds with the same functional group and general formula, differing by \(\ce{–CH2}\)– unit.
Compounds having the same molecular formula but different structural arrangement.
2,4.
Due to catenation, tetravalency, and formation of strong C–C bonds.
A representation showing how atoms are arranged within a molecule.
Representation of valence electrons by dots around chemical symbols, showing covalent bonding.
C is in the center with 4 shared pairs of electrons between C and H atoms \(\ce{(CH4)}\).
An alcohol with formula \(\ce{C2H5OH}\) used in beverages, sanitizers, fuels, and industry.
A carboxylic acid with formula \(\ce{CH3COOH}\), commonly called acetic acid (main component of vinegar).
Reaction of alcohol and acid to form ester + water. Example: \(\ce{C2H5OH + CH3COOH ? CH3COOC2H5 + H2O}\).
Hydrolysis of ester using a base to form soap + alcohol.
Sodium or potassium salts of long-chain fatty acids.
Ammonium or sulphonate salts that work in hard water; stronger cleansing action.
Spherical structure formed by soap molecules in water; hydrophobic ends inward, hydrophilic outward.
Soap micelles trap oily dirt in their hydrophobic cores, allowing water to wash them away.
They do not form scum with calcium and magnesium ions.
Insoluble precipitate formed when soap reacts with \(Ca^{2+}/Mg^{2+} ions in hard water.
Different physical forms of carbon: diamond, graphite, fullerenes.
Each carbon atom forms four strong covalent bonds in a rigid 3D network.
It has free electrons due to layered structure with weak interlayer forces.
A spherical carbon molecule \((C_{60})\) shaped like a football.
Soaps form scum in hard water; detergents do not.
Reactions where atoms add across a double or triple bond (unsaturated compounds).
Reactions where one atom/group is replaced by another (e.g., methane \(+ Cl_2\)).
Addition of oxygen or removal of hydrogen, e.g., alcohol \(\Rightarrow\) acid.
Addition of hydrogen to unsaturated oils to make them saturated fats.
Substances like alkaline \(\ce{KMnO4}\) and acidified \(\ce{K2Cr2O7}\) that add oxygen to compounds.
They lack free ions or electrons.
They consist of molecules held by weak intermolecular forces.
\(\ce{C6H12O6}\).
Molecular formula shows number of atoms; structural formula shows arrangement.
\(\ce{CH4 + 2O2 ? CO2 + 2H2O + \text{heat}}\).
Bromine water decolorization indicates the presence of double/triple bonds.
Identify longest chain \(\Rightarrow\) number it \(\Rightarrow\) identify & locate substituents \(\Rightarrow\) assign prefixes/suffixes (IUPAC rules).
Propane.
Ethene.
Ethyne.
It burns cleanly, producing \(\ce{CO2 + \text{ water}\) with fewer pollutants.
It forms sodium ethoxide + hydrogen gas.
Weakly acidic.
Due to the presence of acetic acid.
Ethanol mixed with toxic substances to make it unfit for drinking.
It forms biomolecules like proteins, fats, carbohydrates, nucleic acids.
Soaps that decompose naturally due to their simple carbon chain structure.
Polar substances dissolve polar ones; non-polar dissolve non-polar.
It dissolves non-polar greasy dirt.
Combustion, oxidation, addition, substitution, esterification, saponification.
Naming, functional groups, reactions, structures, soap/detergent mechanisms, diagrams.
Consecutive members differ by \(\ce{–CH2–}\) and 14 amu in mass.
A mixture of hydrocarbons; raw material for many carbon compounds.
Breaking long hydrocarbon chains into smaller ones (not in NCERT but often asked).
Due to high carbon content.
