Draw formulae for the first four members of each homologous series begining with the following.
(a)`H-COOH` , (b)`H-CH=CH_(2)` , (c )`CH_(3)-oversetoverset(O)(||)(C)-CH_(3)`

Explanation

To solve the question, we need to draw the formulae for the first four members of each homologous series starting with the given compounds:

### (a) Starting with `H-COOH` (Formic Acid - Carboxylic Acid)

1. **First Member**:
- Formula: `HCOOH` (Formic Acid)

2. **Second Member**:
- Add one carbon atom (methyl group) to the first member.
- Formula: `CH3COOH` (Acetic Acid)

3. **Third Member**:
- Add another carbon atom to the second member.
- Formula: `CH3CH2COOH` (Propanoic Acid)

4. **Fourth Member**:
- Add one more carbon atom to the third member.
- Formula: `CH3CH2CH2COOH` (Butanoic Acid)

### Summary for (a):
- 1st: `HCOOH` (Formic Acid)
- 2nd: `CH3COOH` (Acetic Acid)
- 3rd: `CH3CH2COOH` (Propanoic Acid)
- 4th: `CH3CH2CH2COOH` (Butanoic Acid)

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### (b) Starting with `H-CH=CH2` (Ethylene - Alkene)

1. **First Member**:
- Formula: `H2C=CH2` (Ethylene)

2. **Second Member**:
- Add one carbon atom (methyl group) to the first member.
- Formula: `CH3CH=CH2` (Propene)

3. **Third Member**:
- Add another carbon atom to the second member.
- Formula: `CH3CH2CH=CH2` (Butene)

4. **Fourth Member**:
- Add one more carbon atom to the third member.
- Formula: `CH3CH2CH2CH=CH2` (Pentene)

### Summary for (b):
- 1st: `H2C=CH2` (Ethylene)
- 2nd: `CH3CH=CH2` (Propene)
- 3rd: `CH3CH2CH=CH2` (Butene)
- 4th: `CH3CH2CH2CH=CH2` (Pentene)

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### (c) Starting with `CH3-C(=O)-CH3` (Propanone - Ketone)

1. **First Member**:
- Formula: `CH3C(=O)CH3` (Propanone)

2. **Second Member**:
- Add one carbon atom to the first member.
- Formula: `CH3CH2C(=O)CH3` (Butanone)

3. **Third Member**:
- Add another carbon atom to the second member.
- Formula: `CH3CH2CH2C(=O)CH3` (Pentanone)

4. **Fourth Member**:
- Add one more carbon atom to the third member.
- Formula: `CH3CH2CH2CH2C(=O)CH3` (Hexanone)

### Summary for (c):
- 1st: `CH3C(=O)CH3` (Propanone)
- 2nd: `CH3CH2C(=O)CH3` (Butanone)
- 3rd: `CH3CH2CH2C(=O)CH3` (Pentanone)
- 4th: `CH3CH2CH2CH2C(=O)CH3` (Hexanone)

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