Fischer esterification is represented as follows `R-overset(O)overset(||)(C)-overset(16)(O)-H+R'-overset(18)(O)H hArrR-overset(O)overset(||)(C)-overset(A)(O)-R'+H_(2)O` here `(R=CH_(3), R' = C_(2)H_(5))` in the above reaction A/2 is equal to

Options

A. 8
B. 9
C. 6
D. 12

Answer

To solve the problem regarding Fischer esterification and the isotopes involved, we will follow these steps:

### Step 1: Understand the Reaction
Fischer esterification involves the reaction between a carboxylic acid and an alcohol in the presence of an acid catalyst to form an ester and water. In this case, we have a carboxylic acid with a 16O isotope and an alcohol with an 18O isotope.

### Step 2: Identify the Reactants
Given:
- R = CH₃ (methyl group)
- R' = C₂H₅ (ethyl group)

The carboxylic acid can be represented as:
- CH₃COOH (where the oxygen is 16O)

The alcohol can be represented as:
- C₂H₅OH (where the oxygen is 18O)

### Step 3: Write the Reaction
The Fischer esterification reaction can be written as:
\[ \text{CH}_3\text{COOH} + \text{C}_2\text{H}_5\text{OH} \xrightarrow{H^+} \text{CH}_3\text{COOC}_2\text{H}_5 + \text{H}_2\text{O} \]

### Step 4: Analyze the Product
In the product, we have:
- The ester formed is CH₃COOC₂H₅.
- The oxygen in the ester that is attached to the ethyl group (R') is the one we need to analyze for its isotope.

### Step 5: Identify the Isotope of Interest
In the product:
- The oxygen attached to the ethyl group (R') is the one that was originally from the alcohol (C₂H₅OH), which had the 18O isotope.

### Step 6: Determine A
In the product, the oxygen attached to R' (C₂H₅) is labeled as A. Since this oxygen comes from the alcohol with the 18O isotope, we have:
- A = 18

### Step 7: Calculate A/2
Now, we need to find A/2:
\[ A/2 = 18/2 = 9 \]

### Conclusion
Thus, the final answer for A/2 is:
\[ \boxed{9} \]

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