HOMOLOGOUS SERIRS

Which of the compounds shown are in the same homologous series?

• A

  1, 2 and 3

• B

  1, 2 and 4

• C

  1, 3 and 4

• D

  2, 3 and 4

Answer explanation

Compounds 1, 2, and 4 belong to the same homologous series as they share the same functional group and differ by a constant unit (e.g., -CH2-). Compound 3 does not fit this pattern, making option B the correct choice.

Tags

Cambridge GCSE

Cambridge IGCSE

AQA

• A

• B

• C

• D

Answer explanation

The correct answer is C because it does not follow the alkane formula CnH2n+2. Alkanes are saturated hydrocarbons, and any compound that deviates from this formula is not classified as an alkane.

Which compound does not belong to the same homologous series as the other three

compounds?

Answer explanation

The compound C2H5COOH (B) is a carboxylic acid, while the others (CH3OH, C2H5OH, C7H15OH) are alcohols. Therefore, B does not belong to the same homologous series as the other three compounds.

Which homologous series is not represented in the compounds shown below?

• A alcohols

• B alkanes

• C alkenes

• D carboxylic acids

Answer explanation

The compounds shown do not include any alkenes, which are characterized by at least one carbon-carbon double bond. Therefore, the correct answer is C alkenes, as the other series (alcohols, alkanes, carboxylic acids) are represented.

The structures of four compounds are shown.

Which are members of the same homologous series?

• A W, X, Y and Z

• B W and X only

• C W, Y and Z only

• D X and Z only

Answer explanation

Compounds W, Y, and Z share the same functional group and differ by a constant unit, characteristic of a homologous series. Therefore, the correct choice is C: W, Y, and Z only.