Which of the following can give iodoform test?
(I) `CH_(3)-overset(O)overset(||)C-CH_(2)-overset(O)overset(||)C-CH_(3)`
(II) `C_(6)H_(5)-CH_(2)-overset(O)overset(||)C-CH_(3)`
(III) `CH_(3)-CHO`
(IV) `C_(6)H_(5)-overset(O)overset(||)C-CH_(3)`

Options

A. Only IV
B. II and IV
C. III and IV
D. All of these

Answer

To determine which compounds can give the iodoform test, we need to understand the criteria for this test. The iodoform test is positive for carbonyl compounds that have at least one methyl group (–CH₃) adjacent to the carbonyl group (C=O) and at least three alpha hydrogens.

Let's analyze each option step by step:

### Step 1: Analyze Compound I
Compound I: `CH₃-C(=O)-C(=O)-C₂H₅`
- This compound has two carbonyl groups (ketones) and the structure can be simplified to show that it has three alpha hydrogens (from the methyl group).
- Since it has a methyl group adjacent to a carbonyl and three alpha hydrogens, it can give a positive iodoform test.

### Step 2: Analyze Compound II
Compound II: `C₆H₅-CH₂-C(=O)-CH₃`
- This compound is a ketone with a methyl group adjacent to the carbonyl group.
- It has three alpha hydrogens (from the methyl group), satisfying the requirement for the iodoform test.
- Therefore, this compound can also give a positive iodoform test.

### Step 3: Analyze Compound III
Compound III: `CH₃-CHO`
- This compound is an aldehyde with a methyl group adjacent to the carbonyl group.
- It has three alpha hydrogens (from the methyl group), which means it can also give a positive iodoform test.

### Step 4: Analyze Compound IV
Compound IV: `C₆H₅-C(=O)-CH₃`
- This compound is a ketone with a methyl group adjacent to the carbonyl group.
- It has three alpha hydrogens (from the methyl group), thus it can give a positive iodoform test.

### Conclusion
All four compounds (I, II, III, and IV) have the necessary structure to provide a positive iodoform test due to the presence of three alpha hydrogens adjacent to a carbonyl group.

### Final Answer
All options (I, II, III, and IV) can give the iodoform test.

---