Which of the following does not give benoic acid salt on oxidation with hot alkaline `KMnO_(4)`.

Options

A. `Ph-CH_3`
B. `Ph-CH=CH-CH_(3)`
C. `Ph-C-=C-CH_(3)`
D. `Ph-C(CH_(3))_(3)`

Answer

To solve the question of which compound does not give benzoic acid salt upon oxidation with hot alkaline KMnO4, we can follow these steps:

### Step 1: Understand the Reaction
Hot alkaline KMnO4 is a strong oxidizing agent that can oxidize certain organic compounds, particularly those containing alkyl groups attached to aromatic rings. The oxidation typically leads to the formation of carboxylic acids, such as benzoic acid from toluene or similar compounds.

### Step 2: Analyze the Options
We need to analyze each of the provided options to determine whether they can be oxidized to form benzoic acid or not. The key factor is whether the carbon atom attached to the phenyl ring has at least one hydrogen atom.

1. **Option A**: If this compound has a hydrogen atom on the carbon attached to the phenyl ring, it can be oxidized to benzoic acid.
2. **Option B**: Similar analysis as above; check for the presence of a hydrogen atom on the carbon attached to the phenyl ring.
3. **Option C**: Again, check for the hydrogen atom.
4. **Option D**: This compound has a phenyl ring with three methyl (CH3) groups attached to the carbon. Since all three substituents are methyl groups, there is no hydrogen atom on the carbon attached to the phenyl ring.

### Step 3: Conclusion
Based on the analysis, **Option D** does not have a hydrogen atom on the carbon attached to the phenyl ring, which means it cannot be oxidized to form benzoic acid salt. Therefore, the answer is **Option D**.

### Final Answer:
**Option D** does not give benzoic acid salt on oxidation with hot alkaline KMnO4.

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