Explanation

• Ethene (C₂H₄) is an unsaturated hydrocarbon containing a carbon-carbon double bond.
• It decolourises cold, dilute alkaline KMnO₄ solution by undergoing oxidation.
• This test is known as Baeyer's test.
• It is used to detect unsaturation.

Last verified on 02-11-2026

Explanation

• Raney nickel is a porous form of nickel used as a catalyst in hydrogenation reactions.
• It helps add hydrogen (H₂) to unsaturated compounds, converting double or triple bonds into single bonds.
• It is commonly used to convert alkenes into alkanes and in the reduction of various organic compounds.

Last verified on 02-11-2026

Explanation

• Liquid bromine test: Unsaturated compounds decolourise reddish-brown bromine solution due to addition across double or triple bonds.
• Baeyer's reagent: Cold, dilute alkaline potassium permanganate (KMnO₄) is decolourised by unsaturated compounds.
• Both tests are commonly used to detect carbon-carbon double and triple bonds.

Additional information:

• Fehling's solution is mainly used to test reducing sugars and aldehydes.

Last verified on 02-11-2026

Explanation

• The percentage of ethene (ethylene) in coal gas is approximately 2%.

Coal gas is a mixture of several gases, typically composed of:

• • Hydrogen: ~50%
• • Methane: ~30%
• • Carbon Monoxide: ~10%
• • Ethene (Ethylene): ~2%
• • Other gases (Nitrogen, Oxygen, Carbon Dioxide): Remaining %

Last verified on 02-11-2026

Explanation

• The Law of Mass Action was proposed by Norwegian scientists Cato Guldberg and Peter Waage in 1864.
• It states that the rate of a chemical reaction is proportional to the product of the active masses of the reactants, each raised to its stoichiometric power in the reaction equation.
• Active mass generally refers to the effective concentration of a substance.

Last verified on 02-11-2026

Explanation

• The Wurtz reaction involves the reaction of alkyl halides with sodium metal in anhydrous ether.
• Two alkyl groups combine to form a higher alkane.
• General reaction: 2R-X + 2Na -> R-R + 2NaX
• Example: Two molecules of methyl chloride react to form ethane.

Last verified on 02-11-2026

Explanation

• Methane (CH₄) is commonly known as marsh gas.
• Because it is produced in marshes and swamps by the decomposition of organic matter in the absence of oxygen.
• It is the simplest hydrocarbon and the first member of the alkane family.
• Methane is the main component of natural gas.
• It is a potent greenhouse gas and contributes to global warming.

Last verified on 02-11-2026

Explanation

• Both compounds have the same molecular formula, C₂H₆O.
• CH₃–CH₂–OH is ethanol, which contains the alcohol functional group (–OH).
• CH₃–O–CH₃ is dimethyl ether, which contains the ether functional group (–O–).
• Compounds with the same molecular formula but different functional groups are called functional group isomers.

Last verified on 02-11-2026

Explanation

• Position isomerism occurs when the same functional group occupies different positions in the carbon chain.
• Alcohols show position isomerism, such as butan-1-ol and butan-2-ol.
• Alkyl halides and primary amines can also show position isomerism.
• Ethers generally show functional group isomerism, rather than position isomerism, because the oxygen atom connects two alkyl groups.

Last verified on 02-11-2026

Explanation

• Hexane (C₆H₁₄) has five structural isomers.
• These are n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane and 2,3-dimethylbutane.
• All five isomers have the same molecular formula but different carbon-chain arrangements.
• Their physical properties, such as boiling points, are different.

Last verified on 02-11-2026