Carbon and its Compounds Test 2

The carboxylic acid functional group is -COOH, consisting of a carbonyl group (C=O) and a hydroxyl group (-OH) bonded to the same carbon atom. Option A (-COO) represents a carboxylate ion, option C (-OH) is just a hydroxyl group, and option D is incorrect since option B is valid.

Rayon is manufactured by regenerating cellulose from wood pulp or cotton linters through chemical processing. It's classified as a semi-synthetic fiber because it uses natural cellulose but requires chemical transformation. Terylene and polyester are synthetic, while nylon is a polyamide made from petrochemicals, not cellulose.

In a homologous series, each successive member differs by one -CH2- unit (called a methylene group) when moving up or down the series. This constant difference of 14 atomic mass units gives the series its characteristic incremental physical and chemical properties. -CH, -CH4, and -CH3CH2 are not the repeating units.

Ethylene is the common (trivial) name, while ethene is the systematic IUPAC name following the naming convention for alkenes (suffix -ene). Ethane is an alkane, acetylene is the common name for ethyne, and 'none of these' is incorrect since option B is valid.

Nylon is a polyamide, meaning it contains repeating amide (-CONH-) linkages in its polymer chain. It's formed by condensation polymerization between diamines and dicarboxylic acids. Option A is wrong because nylon is not derived from ethylene, option B describes polyalcohols (like PVA), and option D is incorrect terminology.

Polythene (polyethylene) is formed by addition polymerization of ethene molecules. The process breaks the carbon-carbon double bond in ethene and forms long chains of single-bonded carbon atoms with hydrogen atoms. Options B (methane), C (ethane), and D (acetylene/ethyne) do not polymerize to form polythene.

Graphite's layered structure with delocalized electrons between the carbon layers makes it an excellent conductor of electricity, which is the primary reason it's used in electrodes. While options A, C, and D describe some of graphite's properties (metallic luster, crystalline nature, corrosion resistance), these are not the main reasons for electrode use.

Marsh gas is the common name for methane (CH4) because it's produced by anaerobic decomposition of organic matter in marshes and swamps. H2S is hydrogen sulfide (rotten egg gas), C2H4 is ethene, and C2H2 is acetylene - none of which are called marsh gas.

Alkanes are saturated hydrocarbons with the general formula CnH2n+2, where each carbon atom forms four single bonds. For alkenes it's CnH2n, for alkynes it's CnH2n-2, and option D doesn't represent any standard homologous series. The '+2' accounts for the extra hydrogens needed for saturation.

The given compounds CH4, C2H6, and C3H8 are alkanes following the general formula CnH2n+2. The homologous series continues with C4H10 (butane) and C5H12 (pentane). Therefore, the fifth member is C5H12.

Alkenes are hydrocarbons with one carbon-carbon double bond. This reduces the hydrogen count by 2 compared to alkanes, giving the general formula CnH2n where n is the number of carbon atoms.

The hydroxyl group (-OH) is the defining functional group of alcohols. This group consists of an oxygen atom bonded to a hydrogen atom, which gives alcohols their characteristic properties like solubility in water and ability to form hydrogen bonds.

Butane (C4H10) is a short-chain alkane with only 4 carbon atoms. Small alkanes with 1-4 carbon atoms exist as gases at room temperature because they have weak intermolecular forces and low boiling points.

Hydrocarbons with 5-16 carbon atoms (pentane to hexadecane range) are liquids at room temperature. They have sufficient molecular weight and intermolecular forces to exist as liquids, unlike smaller alkanes (gases) or much larger ones (solids).

Alkynes contain a carbon-carbon triple bond. This triple bond reduces the hydrogen count by 4 compared to alkanes (CnH2n+2), resulting in the general formula CnH2n-2 where n is the number of carbon atoms.

Butane is a 4-carbon alkane with the formula C4H10 following the CnH2n+2 pattern for alkanes. Substituting n=4 gives C4H(2×4+2) = C4H10.

Diamond is the hardest known natural material because its carbon atoms are arranged in a rigid tetrahedral structure with strong covalent bonds extending in three dimensions. This makes diamond much harder than other forms of carbon like graphite or charcoal.

Graphite has a layered structure where carbon atoms are arranged in flat sheets. These layers can easily slide over each other due to weak van der Waals forces between them, giving graphite its soft and greasy texture that makes it an excellent solid lubricant.

CH3OH is methanol, which is the IUPAC name for the simplest alcohol containing one carbon atom. The 'meth-' prefix indicates one carbon, and '-anol' suffix indicates the alcohol functional group.

C2H5COOH contains three carbon atoms (two in the ethyl group and one in the carboxyl group). According to IUPAC nomenclature for carboxylic acids, a three-carbon acid is called propanoic acid (prop- for three carbons, -anoic acid for carboxylic acid).

Ethyl alcohol (ethanol) is the primary alcoholic component produced during fermentation in both beer and wine. Methyl alcohol is toxic and appears only in trace amounts, while formic and acetic acids are not major fermentation products.

Heating sodium acetate with sodalime produces methane (CH4) via decarboxylation, not ethylene, ethane, or acetylene. This is a classic laboratory reaction for methane preparation.

Pentane is a 5-carbon alkane, and all alkanes follow the formula CnH2n+2. For n=5, this gives C5H12. The other options represent ethane, propane, and butane respectively.