Deuterium is the isotope of hydrogen of mass number `2`, with a proton and a neutron in its nucleus. The chemistry of deuterium is nearly identical to the chemistry of hydrogen, except that `C-D` bond is slightly `(5.0 "KJ" //"mole")` stonger than the `C-H` bond. Reaction rates tend to be slower if a `C-D` bond as opposed to a `C-H` bond is broken in a rate limiting step. This effect on the rate is called a kinetic isotope effect.
`CH_(3)-overset(O) overset(||)(C)-CH_(3)overset(D_(2)O,D^(+))toX`

Options

A. `CD_(3)-overset(O) overset(||)(C)-CD_(3)`
B. `H_(2)C=overset(OD) overset(|)(C)-CH_(3)`
C. `H_(2)O=overset(OH)overset(|)(C)-CH_(3)`
D. `CH_(3)-overset(O)overset(||)(C)-CD_(3)`

Explanation

To solve the problem, we need to analyze the reaction of a ketone with deuterium oxide (D2O) in the presence of a deuterium ion (D+). The ketone in question is CH3C(=O)CH2 (which can be simplified as CH3C=O with an additional hydrogen on the alpha carbon).

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactant is a ketone, specifically CH3C(=O)CH2, which we can denote as acetone for simplicity.

2. **Introduce Deuterium**:
The reaction involves deuterium oxide (D2O) and a deuterium ion (D+). Deuterium is an isotope of hydrogen, and in this case, we are replacing hydrogen atoms with deuterium atoms.

3. **Mechanism of Reaction**:
When the ketone is treated with D2O, the deuterium ion (D+) will replace one of the hydrogen atoms on the alpha carbon (the carbon adjacent to the carbonyl group). The base (OD-) will abstract a hydrogen atom from the alpha carbon, creating a carbanion intermediate.

4. **Formation of the Intermediate**:
The carbanion formed will be CH3C(=O)C(-)H2 (where (-) indicates a negative charge). This intermediate will then react with D+ to form the product.

5. **Substitution of Deuterium**:
The carbanion will react with D+, leading to the substitution of one hydrogen atom with deuterium. This results in the product CH3C(=O)CD2.

6. **Repeat the Process**:
If we repeat this process, we can replace the remaining hydrogen atoms on the alpha carbon with deuterium. After two more cycles, we will end up with CH3C(=O)CD3.

7. **Final Product**:
The final product after the complete reaction will be CH3C(=O)CD3, which is the deuterated version of acetone.

8. **Select the Correct Option**:
Based on the options provided, the correct answer is the one that represents CH3C(=O)CD3.

### Conclusion:
The final product of the reaction is CH3C(=O)CD3, which corresponds to option D.