Q.Select the correct one: Which of the following represents the general formula of alkenes?

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 …

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: …

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. …

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 …

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): $C_nH_{2n+2}$
• Alkenes (one C=C double bond): $C_nH_{2n}$
• Alkynes (one C≡C triple bond): $C_nH_{2n-2}$ …

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. …

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 …

Each degree of unsaturation removes 2 H atoms from the saturated C$_n$H$_{2n+2}$ formula; a triple bond (2 degrees) gives C$_n$H$_{2n-2}$ — the alkyne formula.

Saturated alkanes follow C$_n$H$_{2n+2}$ (no unsaturation). Each ring or π-bond reduces the H count by 2:

• Alkenes (one C=C double bond, one degree of unsaturation): C$_n$H$_{2n}$.
• Alkynes (one C≡C triple bond, two degrees of unsaturation): C$_n$H$_{2n-2}$. …

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 …

Alkenes are unsaturated hydrocarbons with one C=C double bond, giving the general formula $C_nH_{2n}$ — two hydrogens fewer per molecule than the corresponding alkane ($C_nH_{2n+2}$).

Step 1 — Compare the hydrocarbon families:

• Alkanes (saturated, all single bonds): $C_nH_{2n+2}$ — e.g. ethane $C_2H_6$.
• Alkenes (one C=C double bond): $C_nH_{2n}$ — e.g. ethene $C_2H_4$.
• Alkynes (one C≡C triple bond): $C_nH_{2n-2}$ — e.g. ethyne $C_2H_2$. …