Action of hydrogen chloride on `CH_3-underset(CH_3)underset|C=CH_2` and on `CH-=CH` will predominantly give the compounds, reapectively

Options

A. `CH_3-undersetunderset(CH_3)(|)CH-CH_2Cl` and `CH_2Cl-CH_2Cl`
B. `CH_3-undersetunderset(CH_3)|"CCl"-CH_3` and `CH_3-CHCl_2`
C. `CH_3-undersetunderset(CH_3)(|)CH-CH_2Cl` and `CH_3-CHCl_2`
D. `CH_3-undersetunderset(CH_3)|CH-CH_3` and `CH_2Cl-CH_2Cl`

Explanation

To solve the problem of the action of hydrogen chloride (HCl) on the compounds `CH3C(CH3)=CH2` (isobutene) and `CH≡CH` (acetylene), we can follow these steps:

### Step 1: Identify the Compounds
The first compound is isobutene, which has the structure `CH3C(CH3)=CH2`. The second compound is acetylene, which has the structure `CH≡CH`.

### Step 2: Reaction of HCl with Isobutene
When HCl is added to isobutene, an electrophilic addition reaction occurs. The double bond in isobutene acts as a nucleophile and attacks the hydrogen (H+) from HCl.

1. The H+ from HCl adds to one of the carbon atoms in the double bond, forming a carbocation. The more stable carbocation is formed by adding H+ to the carbon that is more substituted (the one attached to two methyl groups).
2. The resulting carbocation is `CH3C+(CH3)CH2`, which is a tertiary carbocation.
3. The Cl- ion from HCl then attacks the carbocation, resulting in the product `CH3C(CH3)ClCH2`.

### Step 3: Reaction of HCl with Acetylene
When HCl is added to acetylene, a similar electrophilic addition reaction occurs, but since acetylene has a triple bond, the reaction will happen twice.

1. The first addition of HCl to acetylene results in the formation of a vinyl carbocation: `CH2=C^+(H)CH`.
2. The Cl- ion then attacks this carbocation, forming `CH2Cl-CH=CH2` (vinyl chloride).
3. A second addition of HCl will occur, leading to the formation of a geminal dihalide: `CHCl2-CH2`.

### Final Products
- The product from the reaction of HCl with isobutene is `CH3C(CH3)ClCH2` (2-chloro-2-methylpropane).
- The product from the reaction of HCl with acetylene is `CHCl2-CH2` (1,1-dichloroethane).

### Summary of Products
1. For isobutene (`CH3C(CH3)=CH2`), the predominant product is `CH3C(CH3)ClCH2`.
2. For acetylene (`CH≡CH`), the predominant product is `CHCl2-CH2`.