Q.The general formula of ether is
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🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Homologous Series and General Formulas
A homologous series is a run of organic compounds that all share one characteristic functional group, and whose successive members differ from each other in molecular formula by exactly one CH2 unit -- for example the alkanes (methane CH4, ethane C2H6, propane C3H8...) or the alcohols (methanol CH3OH, ethanol C2H5OH, propanol C3H7OH...).
Because every member of a series shares the same functional group and the same CH2-unit spacing, the entire series can be captured by ONE general formula: alkanes are CnH2n+2, alkenes are CnH2n, alkynes are CnH2n−2 -- and since an alkadiene (a chain with two C=C double bonds) has the same degree of unsaturation as an alkyne (one C≡C triple bond, or two degrees of unsaturation total), alkadienes share the alkyne formula, CnH2n−2. This same general-formula logic extends class by class: an aliphatic monohydric alcohol is CnH2n+1OH (one -OH on a saturated chain); aliphatic ketones are CnH2nO (one C=O on a saturated chain, needing at least 3 carbons since the carbonyl carbon needs two carbon substituents); aliphatic amines are CnH2n+3N (one -NH2, or a substituted nitrogen, on a saturated chain); nitroalkanes are CnH2n+1NO2 for the first six members: CH3NO2 (nitromethane), C2H5NO2 (nitroethane), C3H7NO2 (nitropropane), C4H9NO2 (nitrobutane), C5H11NO2 (nitropentane), C6H13NO2 (nitrohexane). …
Ethers are fully saturated compounds with the same degree of unsaturation as their isomeric alcohols, so their general formula matches that of the corresponding monohydric alcohol. …
Ethers (R-O-R') are functional isomers of monohydric alcohols, so both share the general formula CnH2n+2O.
An ether has the structure R-O-R' with only single bonds and no rings, i.e. it is fully saturated. Check with the simplest: dimethyl ether is CH3-O-CH3 = C2H6O, which fits CnH2n+2O for n = 2 (2x2+2 = 6). This is the same …
- CBSE 2026Set A1 markMCQQ.The general formula of ether is(a) CnH2nO(b) CnH2n+1O(c) CnH2n+2O(d) CnH2nO2
›Reveal solutionSolution
Ethers (R-O-R') are functional isomers of monohydric alcohols, so both share the general formula CnH2n+2O.
An ether has the structure R-O-R' with only single bonds and no rings, i.e. it is fully saturated. Check with the simplest: dimethyl ether is CH3-O-CH3 = C2H6O, which fits CnH2n+2O for n = 2 (2x2+2 = 6). This is the same …
- CBSE 2025Set D1 markMCQQ.The general formula of an amine is(a) CnH2n+1N(b) CnH2n+2N(c) CnH2n+3N(d) CnH2nN
›Reveal solutionSolution
A saturated amine has the general formula CnH2n+3N.
A saturated aliphatic hydrocarbon is CnH2n+2. An amine is formed by replacing one hydrogen with an -NH2 (or by attaching nitrogen bearing hydrogens). Adding nitrogen with its extra hydrogens raises the hydrogen count by one relative to the alkane: …
- CBSE 2025Set D1 markMCQQ.The general formula of carbonyl compound is(a) CnH2nO(b) CnH2n+2O(c) CnH2n+1O(d) none of these
›Reveal solutionSolution
Saturated aldehydes and ketones (carbonyl compounds) share the general formula CnH2nO.
Carbonyl compounds are aldehydes (R-CHO) and ketones (R-CO-R'). For saturated members, the general molecular formula is CnH2nO. For example: HCHO (n=1, CH2O), CH3CHO (n=2, C2H4O), CH3COCH3 (n=3, C3H6O) — each fits CnH2nO. …
- CBSE 2025Set sz1 markMCQQ.Select the correct one: Which of the following represents the general formula of alkenes?(a) CnH2n(b) CnH2n-2(c) CnH2n+2(d) CnH2n+1
›Reveal solutionSolution
The general formula of alkenes (one C=C double bond) is CnH2n.
Saturated open-chain hydrocarbons (alkanes) have the general formula CnH2n+2. Each degree of unsaturation (one double bond or one ring) removes 2 hydrogen atoms from this formula. Alkenes contain exactly one C=C double bond, so their general formula is CnH2n+2 - 2 = CnH2n. (CnH2n-2 is the formula for alkynes/diene …
- CBSE 2025Set ANNUAL1 markMCQQ.The general formula of alkene is(a) CnH2n+1(b) CnH2n+2(c) CnH2n-1(d) CnH2n
›Reveal solutionSolution
Alkenes (one C=C double bond, one degree of unsaturation) follow CnH2n.
The general formulas of the common acyclic hydrocarbon families are:
- Alkanes (saturated, no double/triple bonds): CnH2n+2
- Alkenes (one C=C double bond): CnH2n
- Alkynes (one C≡C triple bond): CnH2n−2 …
- CBSE 2024Set D1 markMCQQ.The general molecular formula of saturated monocarboxylic acids is(a) CnH2n+2O(b) CnH2nO(c) CnH2nO2(d) CnH2n+1O2
›Reveal solutionSolution
Saturated monocarboxylic acids: CnH2nO2.
A saturated monocarboxylic acid has one -COOH group. Checking with examples:
- Formic acid HCOOH → CH2O2 (n=1): C1H2O2 fits CnH2nO2.
- Acetic acid CH3COOH → C2H4O2 (n=2): fits CnH2nO2.
- Propionic acid C2H5COOH → C3H6O2 (n=3): fits. …
- CBSE 2022Set ANNUAL1 markQ.The formula of Alkene is ................. (Fill in the blank)
›Reveal solutionSolution
The general formula of an alkene is CnH2n.
Alkenes are unsaturated hydrocarbons containing one carbon-carbon double bond (C=C). Because of the double bond, an alkene has two fewer hydrogen atoms than the corresponding saturated alkane (CnH2n …
- CBSE 2022Set ANNUAL1 markMCQQ.CnH2n-2 is general formula of :(a) Alkanes(b) Arenes(c) Alkenes(d) Alkynes
›Reveal solutionSolution
Each degree of unsaturation removes 2 H atoms from the saturated CnH2n+2 formula; a triple bond (2 degrees) gives CnH2n−2 — the alkyne formula.
Saturated alkanes follow CnH2n+2 (no unsaturation). Each ring or π-bond reduces the H count by 2:
- Alkenes (one C=C double bond, one degree of unsaturation): CnH2n.
- Alkynes (one C≡C triple bond, two degrees of unsaturation): CnH2n−2. …
- CBSE 2021Set A1 markMCQQ.The general formula of monohydric alcohol is(a) CnH2n+1OH(b) CnH2n+2OH(c) CnH2nOH(d) None of these
›Reveal solutionSolution
Monohydric alcohol = alkyl-OH = CnH2n+1OH.
A monohydric alcohol contains one hydroxyl (-OH) group attached to a saturated alkyl group. A saturated alkyl group has the formula CnH2n+1 (e.g. CH3-, C2H5-). Attaching -OH gives the general formula CnH2n+1OH, e …
- CBSE 2021Set ANNUAL1 markMCQQ.CnH2n is general formula of:(a) alkene(b) alkane(c) alkyne(d) arene
›Reveal solutionSolution
Alkenes are unsaturated hydrocarbons with one C=C double bond, giving the general formula CnH2n — two hydrogens fewer per molecule than the corresponding alkane (CnH2n+2).
Step 1 — Compare the hydrocarbon families:
- Alkanes (saturated, all single bonds): CnH2n+2 — e.g. ethane C2H6.
- Alkenes (one C=C double bond): CnH2n — e.g. ethene C2H4.
- Alkynes (one C≡C triple bond): CnH2n−2 — e.g. ethyne C2H2. …
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