Assertion Reasoning questions (MCQ)

Class 10
Chapter 4 Class 10 - Carbon and its Compounds

## Reason (R): A series of compounds with same functional group but differing by ––CH 2 – unit is called a homologous series.

Homologous series is a group/sequence of compounds which have the same functional group and similar chemical properties .

The two successive compounds differ by a CH 2 group i.e. 12+(2x1)=14 amu

Since CH 3 OH, CH 3 CH 2 OH, CH 3 CH 2 CH 2 OH all have similar functional groups (OH) and 2 successive compounds differ by CH 2 they belong to the same homologous group.

Thus,

• Assertion is true.
• Reasoning is true.
• And reasoning is the correct explanation of Assertion.

So, the correct answer is (a) both assertion and reason are correct and reason is the correct explanation for the assertion.

### Transcript

Assertion (A): Following are the members of a homologous series: CH3OH, CH3CH2OH, CH3CH2CH2OH Reason (R): A series of compounds with same functional group but differing by ––CH2 – unit is called a homologous series. Answer Homologous Series Alkanes Alkynes Alcohols CH4 C2H6 C3H8 C4H10 CH2 CH2 CH2 C2H2 C3H4 C4H6 C5H8 CH2 CH2 CH2 CH3OH C2H5OH C3H7OH C4H9OHCH2 CH2 CH2 CH2 Homologous series is a group/sequence of compounds which have the same functional group and similar chemical properties. The two successive compounds differ by a CH2 group i.e. 12+(2x1)=14 amu Since CH3OH, CH3CH2OH, CH3CH2CH2OH all have similar functional groups (OH) and 2 successive compounds differ by CH2 they belong to the same homologous group. Thus, Assertion is true. Reasoning is true. And reasoning is the correct explanation of Assertion. So, the correct answer is (a) both assertion and reason are correct and reason is the correct explanation for the assertion.