`Aoverset(redP)underset(HI)larrCH_(3)COOHoverset(LiAlH_(4))rarrB`. What is not true for A and B ?

Options

A. A is hydrocarbon of general formula `C_(n)H_(2n+2)` while B belong to alkanol
B. A can be obtained by reducing `CH_(3)CH_(2)Cl` while by is alkanal
C. A and B both belongs to different homologous series
D. A and B both belongs to different homologous series

Answer

To solve the question, let's analyze the chemical reactions and the properties of compounds A and B step by step.

### Step 1: Identify Compound A
The question states that compound A reacts with red phosphorus and HI to yield CH3COOH (acetic acid). The reaction can be represented as follows:

\[ A + \text{red P} + \text{HI} \rightarrow \text{CH}_3\text{COOH} \]

From the video transcript, we know that A is ethane (C2H6). This is because when ethane is treated with red phosphorus and HI, it can lead to the formation of acetic acid.

### Step 2: Identify Compound B
Next, the compound A (which we identified as CH3CH3 or ethane) is treated with lithium aluminium hydride (LiAlH4). This is a reduction reaction, and it converts acetic acid (CH3COOH) into ethanol (C2H5OH).

\[ \text{CH}_3\text{COOH} + \text{LiAlH}_4 \rightarrow B \]

Thus, compound B is ethanol (C2H5OH).

### Step 3: Analyze the Properties of A and B
Now we need to analyze the properties of A and B:

1. **A is a hydrocarbon**: Ethane (C2H6) is a saturated hydrocarbon, satisfying the general formula CnH2n+2.
2. **B is an alcohol**: Ethanol (C2H5OH) belongs to the alcohol functional group.
3. **Different Homologous Series**: A (alkane) and B (alcohol) belong to different homologous series.

### Step 4: Determine What is Not True for A and B
Now, we need to identify which of the statements about A and B is not true:

1. A is a hydrocarbon of the general formula CnH2n+2 (True).
2. A can be obtained by reducing CH3CH2Cl (True).
3. A and B belong to different homologous series (True).
4. A and B both belong to the same homologous series (Not True).

### Conclusion
The statement that is not true for A and B is that they belong to the same homologous series. A is an alkane, while B is an alcohol, thus they belong to different series.