Consider the following reaction sequence
`CH_(3)C-=CHunderset(" 2 mole")overset(HCl)rarrAunderset("Heat")overset(aq. KOH)rarrB`
The products (A) and (B) are, respectively,

Options

A. `CH_(3)CH_(2)CHCl_(2)` and `CH_(3)CH_(2)CHO`
B. `CH_(3)C Cl_(2)CH_(3)` and `CH_(3)COCH_(3)`
C. `CH_(3)C Cl_(2)CH_(3)` and `CH_(3)-=CH`
D. `CH_(3)CHCICH_(2)Cl` and `CH_(3)CHOHCH_(2)OH`

Answer

To solve the given reaction sequence, we will follow the steps outlined in the video transcript and provide a detailed explanation of the reactions involved.

### Step-by-Step Solution:

1. **Identify the Starting Material**:
The starting material is propyne, which has the structure:
\[ \text{CH}_3\text{C} \equiv \text{CH} \]

2. **First Reaction with HCl**:
When propyne reacts with 2 moles of HCl, we will have an electrophilic addition reaction. According to Markovnikov's rule, the hydrogen (H) from HCl will add to the carbon with more hydrogen atoms (the terminal carbon), while the chlorine (Cl) will add to the other carbon. The first addition will yield:
\[ \text{CH}_3\text{C}(\text{H})\text{Cl}\text{CH}_2 \]
This product is a vinyl halide.

3. **Second Reaction with HCl**:
Since we are using 2 moles of HCl, we will have another electrophilic addition. The second mole of HCl will add to the other carbon atom, resulting in:
\[ \text{CH}_3\text{C}(\text{Cl})\text{Cl}\text{CH}_3 \]
This product (A) is 2,2-dichloropropane.

4. **Reaction with Aqueous KOH**:
The product A (2,2-dichloropropane) will now react with aqueous KOH. In this reaction, the Cl atoms will be replaced by OH groups. This substitution will yield:
\[ \text{CH}_3\text{C}(\text{OH})\text{Cl}\text{CH}_3 \]
After this step, we have a compound that is still not stable.

5. **Heating the Product**:
Heating will lead to the elimination of HCl and the formation of a double bond. The resulting product (B) will be:
\[ \text{CH}_3\text{C}=\text{O}\text{CH}_3 \]
This compound is acetone (or propan-2-one).

### Final Products:
- Product A: 2,2-dichloropropane (CH3CCl2CH3)
- Product B: Acetone (CH3COCH3)

### Summary:
Thus, the products (A) and (B) are respectively:
- A: 2,2-dichloropropane
- B: Acetone