Arrange the following alcohols in order of increasing reactivity towards sodium metal.
(i) `CH_(3)OH`
(ii) `(CH_(3))_(2)CH-OH`
(iii) `CH_(3)CH_(2)OH`
(iv) `(CH_(3))_(3)C-OH`

Options

A. (iv) > (iii) > (ii) >(i)
B. (ii) < (i) < (iii) <(iv)
C. (iv) < (ii) < (iii) < (i)
D. (i) > (iii)> (ii) >(iv)

Answer

To solve the problem of arranging the given alcohols in order of increasing reactivity towards sodium metal, we need to consider the structure of each alcohol and the acidity of the hydroxyl (–OH) group. The reactivity of alcohols with sodium metal is influenced by the acidity of the hydrogen atom attached to the hydroxyl group. More acidic alcohols will react more readily with sodium, releasing hydrogen gas.

### Step-by-step Solution:

1. **Identify the Alcohols:**
- (i) `CH₃OH` (Methanol)
- (ii) `(CH₃)₂CH-OH` (Isopropanol)
- (iii) `CH₃CH₂OH` (Ethanol)
- (iv) `(CH₃)₃C-OH` (Tert-butanol)

2. **Determine the Degree of Alcohol:**
- Methanol (i) is a primary alcohol (1°).
- Isopropanol (ii) is a secondary alcohol (2°).
- Ethanol (iii) is a primary alcohol (1°).
- Tert-butanol (iv) is a tertiary alcohol (3°).

3. **Assess Acidity:**
- The acidity of alcohols generally increases with the degree of substitution. Tertiary alcohols are less acidic than secondary, which are less acidic than primary alcohols due to the electron-donating effects of alkyl groups.
- Therefore, the order of acidity (and thus reactivity with sodium) is:
- Tertiary alcohols (least acidic) < Secondary alcohols < Primary alcohols (most acidic).

4. **Rank the Alcohols:**
- Tert-butanol (iv) will be the least reactive due to being a tertiary alcohol.
- Isopropanol (ii) will be more reactive than tert-butanol but less than primary alcohols.
- Ethanol (iii) and Methanol (i) are both primary alcohols, but methanol is slightly more acidic than ethanol due to less steric hindrance.
- Thus, the order of increasing reactivity is:
- Tert-butanol (iv) < Isopropanol (ii) < Ethanol (iii) < Methanol (i).

5. **Final Arrangement:**
- The increasing order of reactivity towards sodium metal is:
- (iv) < (ii) < (iii) < (i)
- In numerical terms: 4 < 2 < 3 < 1.

### Conclusion:
The final order of increasing reactivity towards sodium metal is:
**(iv) < (ii) < (iii) < (i)**