The yield of ketone when a secondary alcohol is oxidised is more than the yeild of aldehyde when a primary alcohol is oxidised.

Explanation

To understand why the yield of ketone from the oxidation of a secondary alcohol is greater than the yield of aldehyde from the oxidation of a primary alcohol, let’s break down the process step by step.

### Step 1: Identify the Types of Alcohols
- **Primary Alcohol**: An alcohol where the hydroxyl (-OH) group is attached to a carbon that is bonded to only one other carbon (R-CH2OH).
- **Secondary Alcohol**: An alcohol where the hydroxyl (-OH) group is attached to a carbon that is bonded to two other carbons (R1-CHOH-R2).

### Step 2: Oxidation of Primary Alcohol
- When a primary alcohol (R-CH2OH) is oxidized, it is converted into an aldehyde (R-CHO).
- The reaction can be represented as:
\[ R-CH2OH \xrightarrow{[O]} R-CHO \]

### Step 3: Further Oxidation of Aldehyde
- The aldehyde formed (R-CHO) can undergo further oxidation to produce a carboxylic acid (R-COOH).
- The reaction can be represented as:
\[ R-CHO \xrightarrow{[O]} R-COOH \]
- This means that not all of the aldehyde formed from the primary alcohol will remain as aldehyde; some will be converted to carboxylic acid.

### Step 4: Oxidation of Secondary Alcohol
- When a secondary alcohol (R1-CHOH-R2) is oxidized, it is converted into a ketone (R1-CO-R2).
- The reaction can be represented as:
\[ R1-CHOH-R2 \xrightarrow{[O]} R1-CO-R2 \]

### Step 5: Stability of Ketones
- Ketones (R1-CO-R2) are generally more stable than aldehydes and do not undergo further oxidation under mild conditions.
- Therefore, once the secondary alcohol is oxidized to a ketone, it remains as a ketone and does not convert to any further oxidation products.

### Conclusion
- The yield of ketone from the oxidation of a secondary alcohol is higher because the ketone does not undergo further oxidation, while the aldehyde from the primary alcohol can be further oxidized to a carboxylic acid. Thus, the total amount of aldehyde that can be isolated is less than that of the ketone.

### Summary
- **Primary Alcohol** → **Aldehyde** → **Carboxylic Acid** (some aldehyde is lost)
- **Secondary Alcohol** → **Ketone** (no further oxidation)