Treatment of 1-butene with conc. `H_2SO_4` followed by treatment with water forms

Options

A. 1-butanol
B. 2-butanol
C. 2-propanol
D. 1,2-propandiol

Explanation

To solve the problem of what product is formed when 1-butene is treated with concentrated sulfuric acid followed by water, we can follow these steps:

### Step 1: Identify the Structure of 1-Butene
1-butene is an alkene with the molecular formula C4H8. Its structure can be represented as:
```
H H H
| | |
H--C==C--C--C--H
| | |
H H H
```
This shows a four-carbon chain with a double bond between the first and second carbon atoms.

**Hint:** Remember that alkenes have a double bond which is reactive in electrophilic addition reactions.

### Step 2: Reaction with Concentrated H2SO4
When 1-butene is treated with concentrated sulfuric acid (H2SO4), the double bond reacts with the acid. According to Markovnikov's rule, the hydrogen from H2SO4 will add to the carbon with more hydrogen atoms (the first carbon), leading to the formation of a carbocation on the second carbon:
```
H H H
| | |
H--C--C^+--C--C--H
| | |
H H H
```
Here, the carbocation is formed on the second carbon (C2).

**Hint:** Markovnikov's rule states that the more substituted carbon will receive the positive charge in the formation of a carbocation.

### Step 3: Formation of Alkyl Hydrogen Sulfate
The negatively charged bisulfate ion (HSO4-) from the sulfuric acid will then bond to the carbocation, resulting in the formation of an alkyl hydrogen sulfate:
```
H H H
| | |
H--C--C--C--C--H
| | |
H H H
|
O-SO3H
```

**Hint:** The alkyl hydrogen sulfate is an intermediate that will be hydrolyzed in the next step.

### Step 4: Hydrolysis with Water
Next, the alkyl hydrogen sulfate is treated with water. The water will provide hydroxide ions (OH-) that will attack the carbon atom where the alkyl hydrogen sulfate is attached. This leads to the substitution of the sulfate group with a hydroxyl group:
```
H H H
| | |
H--C--C--C--C--H
| | |
H H OH
```
This results in the formation of 2-butanol.

**Hint:** Hydrolysis involves the substitution of a leaving group (in this case, the sulfate group) with a hydroxyl group.

### Step 5: Naming the Product
The product formed is 2-butanol. The longest carbon chain has four carbons (butane), and the hydroxyl group (-OH) is on the second carbon, hence the name 2-butanol.

**Hint:** Use IUPAC naming rules to identify the longest chain and the position of functional groups.

### Final Answer
The product formed from the treatment of 1-butene with concentrated H2SO4 followed by water is **2-butanol**.